Heat exchange reformer unit and reformer system

ABSTRACT

In a heat exchange reformer unit, a reforming passage supporting reform catalyst for inducing reforming reactions and a combustion passage supporting oxidizing catalyst for combustion are disposed adjacent to each other with a plate portion interposed therebetween. Heat-exchanging passages of the reforming passage that produce reformate gas that contains hydrogen from supplied reformation material, and heat-exchanging passages of the combustion passage that supply heat, which is generated by catalytically burning supplied fuel, to the reforming passage constitute a parallel-flow heat exchanger. Reformation material guide passages for introducing reformation material into the heat-exchanging passages in a predetermined direction, and mixed gas guide passages for introducing fuel into the heat-exchanging passages in a direction intersecting the gas flow direction in the reformation material guide passages, are provided upstream of the heat-exchanging passages in a gas flow direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchange reformer unit in whichreforming reactions are caused by which reformate gas that containshydrogen is obtained from reformation material, such as hydrocarbon,with heat supplied from a heating section to a reforming section. Thepresent invention also relates to a reformer system including such aheat exchange reformer unit.

2. Description of the Related Art

A cross-flow heat exchange fuel reformer is available in which reformingpassages for producing gas that contains hydrogen by reforminghydrocarbon material and combustion passages for burning fuel gas tosupply heat, which is used in reforming reactions, to the reformingpassages are alternately formed (see Japanese Patent ApplicationPublication No. 2004-244230 (JP-A-2004-244230)). JP-A-2004-244230describes a technology for setting a region in which catalyst is notsupported between plates so that the distribution of heat generationcaused by combustion reactions and the distribution of heat absorptionby reforming reactions in the regions between the plates are adjusted toeach other.

Although, in the cross-flow heat exchange fuel reformer according to therelated art, the way to match the region in which a lot of heat isgenerated by combustion reactions, and the region in which a lot of heatis absorbed by reforming reactions is devised, there is room forimprovement to enhance the heat exchange efficiency by matching theendothermic region and the exothermic region. In addition, because, in afuel reformer, the difference between the reaction velocity of thereforming reactions (mainly, steam reforming reaction) in the reformingpassages and the reaction velocity of the combustion reactions in thecombustion passages is large, that is, the difference in the amount ofreaction per volume between the reforming passages and the combustionpassages is large, there has been a limit to the improvement in thereforming efficiency of the system when the configuration is adopted inwhich the reforming passages and combustion passages are merelyalternately formed in the stacking direction as described above.

SUMMARY OF THE INVENTION

The present invention provides a heat exchange reformer unit of whichthe efficiency of heat exchange between a heating section and areforming section is excellent. The present invention also provides aheat exchange reformer unit and a reformer system, which make itpossible to improve reforming efficiency.

A heat exchange reformer unit according to a first aspect of the presentinvention includes: a reforming section, in which reforming catalyst forinducing reforming reactions is supported, for producing reformats gas,which contains hydrogen, from supplied reformation material throughreforming reactions including steam-reforming reaction; a heatingsection, which is disposed adjacent to the reforming section with aseparation wall interposed between the heating section and the reformingsection so as to cause a gas flow in the same direction as that of a gasflow in the reforming section, and in which oxidizing catalyst forcatalytic combustion is supported, for supplying, to the reformingsection, heat generated by catalytically burning supplied fuel; areformation material-introducing section, one end of which serves as asupply port of the reformation material, and the other end of which isintegral with a reformation material inflow side of the reformingsection; and a fuel-introducing section, one end of which serves as asupply port of the fuel, and the other end of which is integral with afuel inflow side of the heating section, for introducing the fuel intothe heating section in a flow direction different from a flow directionof the reformation material in the reformation material-introducingsection.

In the heat exchange reformer unit according to the first aspect,reforming reactions are caused (promoted) in the reforming section bybringing supplied reformation material into contact with the reformingcatalyst with heat supplied from the heating section, so that reformategas that contains hydrogen is obtained. Reforming reactions create ahighly endothermic region near the end portion on the upstream side (onthe reformation material supply side) of the region in which thereforming catalyst is supported. Combustion reactions create a highlyexothermic region near the end portion on the upstream side (on the fuelsupply side) of the region in which the oxidizing catalyst is supported.

The direction in which the reformation material (or the reformate gas)flows in the reforming section, and the direction in which the fuel orfuel gas flows in the heating section are the same. In other words, theheating section and the reforming section constitute a parallel-flowheat exchange reformer unit. Accordingly, it is possible to create thehighly endothermic region, which is created by the combustion reactionsin the heating section, and the highly exothermic region, which iscreated by the reforming reactions in the reforming section, on the sameside (upstream side) of the regions, in which the catalysts aresupported, in the gas flow direction. Thus, it is possible to locate theregion in which a large amount of heat is generated, close to the regionin which endothermic demand is large (that is, to match the endothermicdistribution and the exothermic distribution).

In this heat exchange reformer, the reformation material-introducingsection, which is integral with the upstream side of the reformingsection, and the fuel-introducing section, which is integral with theupstream side of the heating section in which the gas flow direction isparallel to that in the reforming passage (that is, the gas inlet portsof the reforming section and the heating section of, so to speak, theheat exchanger are positioned at virtually the same position), areconstructed so as to cause gases to flow in directions different fromeach other. In other words, the reformation material-introducing sectionand the fuel-introducing section constitute a quasi cross-flow section.Thus, it is possible to allow the supply port of the reformationmaterial and the supply port of the fuel to be open separately.Accordingly, it is made possible to separately supply reformationmaterial and fuel to the same side of the reforming section and theheating section, and it is possible to construct a parallel-flow heatexchange reformer unit in which the region, in which a large amount ofheat is generated, is located near the region, in which endothermicdemand is large, as described above.

As described above, the heat exchange reformer unit according to thefirst embodiment has excellent efficiency of heat exchange between theheating section and the reforming section. In addition, because heat isexchanged between the reformation material flowing through thereformation material-introducing section and the fuel flowing throughthe fuel-introducing section, the stability (robustness) of operation isenhanced, and it is made possible to realize stable operation againstfluctuations (variation in the temperature of the reformation material,for example).

In the heat exchange reformer unit according to this aspect, theentirety of the fuel-introducing section may be a region in which nooxidizing catalyst is supported.

In the heat exchange reformer unit according to this aspect, oxidizingcatalyst is not supported in the fuel-introducing section, andtherefore, catalytic combustion does not occur in the fuel-introducingsection. Thus, the situation is prevented in which heat generated bycatalytic combustion is not used in the reforming section and causeslocal high-temperature regions to occur. In particular, even in the caseof adopting configurations in which reforming catalyst is supported inthe reformation material-introducing section, local high-temperatureregions can occur because the position of the highly endothermic regionand the position of the highly exothermic region are not matched whenoxidizing catalyst is supported in the fuel-introducing section, which,together with the reformation material-introducing section, forms aquasi cross-flow section described above. However, when oxidizingcatalyst is not supported in the fuel-introducing section, occurrence oflocal high-temperature regions is effectively prevented.

In the heat exchange reformer unit according to this aspect, a pluralityof the reforming sections and a plurality of the heating sections may beprovided, and may be stacked with at least part of the plurality of thereforming sections being adjacent to at least part of the plurality ofthe heating sections, the reformation material-introducing section maybe provided for each of the reforming sections, and surface planes ofthe reformation material supply ports may be substantially on the sameplane, and the fuel-introducing section may be provided for each of theheating sections, and surface planes of the fuel supply ports may besubstantially on the same plane.

In the heat exchange reformer unit according to this aspect, theplurality of the reforming sections and the plurality of the heatingsections are stacked, and at least part of the reforming sections areadjacent to at least part of the heating sections. The number of theheating sections provided may be equal to or less than that of thereforming sections, and every heating section may be adjacent to thereforming section on each side of the heating section in the stackingdirection. Because the reformation material-introducing sections thatare open on the same surface plane are provided in the respective layersof the reforming sections, and the fuel-introducing sections that areopen on the same surface plane are provided in the respective layers ofthe reforming sections, it is possible to separately supply reformationmaterial and fuel to the same side of the reforming sections and theheating sections. Thus, it is possible to construct a parallel-flow heatexchange reformer unit, in which the region in which a large amount ofheat is generated is located close to the region in which endothermicdemand is large, with a multilayer structure showing excellent heatexchange efficiency.

In the heat exchange reformer unit according to this aspect, the heatexchange reformer unit may be constructed by stacking a plurality ofreforming section-forming plate members and a plurality of heatingsection-forming plate members in a predetermined pattern. Each of thereforming section-forming plate members includes: a first flat-shapedplate portion; and a first standing wall provided on the firstflat-shaped plate portion in a standing condition for guiding thereformation material in a predetermined direction, wherein a first heatexchanging section constituting the reforming section together withanother plate portion is formed of part of the first flat-shaped plateportion, and wherein a reformation material guide section constitutingthe reformation material-introducing section together with another plateportion is formed of part of the first flat-shaped plate portion and thefirst standing wall that is formed adjacent to a reformation materialsupply-side of the first heat exchanging section. Each of the heatingsection-forming plate members includes: a second flat-shaped plateportion; and a second standing wall provided on the second flat-shapedplate portion in a standing condition for guiding the fuel in adirection intersecting the predetermined direction, wherein a secondheat exchanging section constituting the heating section together withanother plate portion is formed of part of the second flat-shaped plateportion, and wherein a fuel guide section constituting thefuel-introducing section together with another plate portion is formedof part of the second flat-shaped plate portion and the second standingwall that is formed adjacent to a fuel supply-side of the second heatexchanging section.

In the heat exchange reformer unit according to this aspect, thereforming section-forming plate members and the heating section-formingplate members are stacked in a predetermined pattern, so that thereforming sections and the heating sections are formed between the heatexchanging sections in the plate portions, and the reformationmaterial-introducing sections and the fuel-introducing sections areformed between the reformation material guide sections and the fuelguide sections in the plate portions. Specifically, by stacking thereforming section-forming plate members and the heating section-formingplate members in a predetermined pattern, the reformationmaterial-introducing sections and the fuel-introducing sections areintegrally formed on the upstream side of the parallel-flowheat-exchanging sections, wherein the reformation material-introducingsections and the fuel-introducing sections have the reformation materialsupply ports and the fuel supply ports, respectively, which are openseparately.

The heat exchange reformer unit according to this aspect may furtherinclude: a reformation material manifold, defining a collection space towhich the reformation material supply ports of the plurality of thereformation material-introducing sections are open, for distributing thereformation material to the plurality of the reformationmaterial-introducing sections; and a fuel manifold, defining acollection space to which the fuel supply ports of the plurality of thefuel-introducing sections are open, for distributing the fuel to theplurality of the fuel-introducing sections.

In the heat exchange reformer unit according to this aspect, the supplyports of the reformation material-introducing sections for introducingreformation material into the reforming sections of the respectivelayers are open to the reformation material manifold, and the supplyports of the fuel-introducing sections for introducing fuel into theheating sections of the respective layers are open to the fuel manifold.Thus, it is possible to evenly distribute reformation material from thereformation material manifold to the reforming sections of therespective layers through the reformation material-introducing sectionsof the respective layers. Similarly, it is possible to evenly distributefuel from the fuel manifold to the heating sections of the respectivelayers through the fuel-introducing sections of the respective layers.In particular, by providing the fuel manifold with a mixer for mixingfuel and combustion-supporting gas, it is made possible to supply mixedgas, which is previously mixed immediately upstream of the heatingsections of the respective layers, to the heating sections of therespective layers. In this case, occurrence of the regions in which fuelconcentration is locally high is prevented, and thus, occurrence oflocal high-temperature regions in the heating sections is prevented.

The heat exchange reformer unit according to this aspect may furtherinclude: a reformate gas-discharging section, one end of which serves asa discharge port of the reformate gas, and the other end of which isintegral with a reformate gas outflow side of the reforming section; anda combustion exhaust gas-discharging section, one end of which serves asa discharge port of combustion exhaust gas of the heating section, andthe other end of which is integral with a combustion exhaust gas outflowside of the heating section, for introducing the combustion exhaust gasto the discharge port of the combustion exhaust gas in a flow directiondifferent from a flow direction of the reformate gas in the reformategas-discharging section.

In this heat exchange reformer according to this aspect, the reformategas-discharging section, which is integral with the downstream side ofthe reforming section, and the combustion exhaust gas-dischargingsection, which is integral with the downstream side of the heatingsection in which the gas flow direction is parallel to that in thereforming passage (that is, the gas outlet ports of the reformingsection and the heating section of, so to speak, the heat exchanger arepositioned at virtually the same position), are constructed so as tocause gases to flow in directions different from each other. In otherwords, the reformate gas-discharging section and the combustion exhaustgas-discharging section constitute a quasi cross-flow section. Thus, itis possible to allow the discharge port of the reformate gas and thedischarge port of the combustion exhaust gas to be open separately.Accordingly, it is made possible to separately discharge reformate gasand combustion exhaust gas to the same side of the reforming section andthe heating section, and it is possible to construct a parallel-flowheat exchange reformer unit in which the region, in which a large amountof heat is generated, is located near the region in which endothermicdemand is large, as described above.

In the configuration in which a plurality of reforming sections and aplurality of heating sections are stacked so that at least part of thereforming sections are adjacent to at least part of the heatingsections, the reformate gas-discharging sections may be provided for thereforming sections of the respective layers, and the combustion exhaustgas-discharging sections may be provided for the heating sections of therespective layers. In particular, in the case of a configuration inwhich the reforming section-forming plate members and the heatingsection-forming plate members are stacked in a predetermined pattern,the configuration as described below may be adopted. Specifically, thereformate gas guide section is formed in the plate portion of thereforming section-forming plate member on the side of theheat-exchanging section opposed to the reformation material guidesection. On the reformate gas guide section, the standing walls forguiding reformate gas in another predetermined direction are provided ina standing condition, and the reformate gas guide section constitutesthe reformate gas-discharging section together with another plateportion. Meanwhile, the exhaust gas guide section is formed in the plateportion of the heating section-forming plate member on the side of theheat-exchanging section opposed to the fuel guide section. On theexhaust gas guide section, the standing walls for guiding combustionexhaust gas in a direction intersecting the another predetermineddirection in the reforming section-forming plate member are provided ina standing condition, and the exhaust gas guide section constitutes thecombustion exhaust gas-discharging section together with another plateportion. With this configuration, by stacking the reformingsection-forming plate members and the heating section-forming platemembers in a predetermined pattern, it is possible to separately providethe inlet port and the outlet port of the respective gas of aparallel-flow heat exchanger.

A heat exchange reformer according to a second aspect of the presentinvention includes: a plurality of reforming sections for producingreformate gas, in which reforming catalyst for inducing reformingreactions is supported; and a plurality of heating sections, in whichreforming catalyst for catalytic combustion is supported, for supplyingheat, which is generated by catalytically burning supplied fuel, to thereforming sections, wherein the number of the heating sections is lessthan the number of the reforming sections.

In the heat exchange reformer unit according to this aspect, reformategas is obtained by bringing supplied reformation material into contactwith the reforming catalyst in the reforming section with combustionheat supplied from the heating section to cause (promote) reformationreactions. In the meantime, because the reaction velocity of reformingreactions is lower than that of combustion reactions, reformingreactions require a reaction space (volume) larger than that ofcombustion reactions. In the heat exchange reformer unit according tothis aspect, the number of layers of the reforming sections is greaterthan the number of layers of the heating sections, the difference in theamount of reaction per volume between the reforming passages and thecombustion passages is compensated by the difference in the number oflayers thereof (the volume of reaction space). That is, the amount ofreaction is set according to the reaction field, and it is possible toincrease the amount of reformate gas produced relative to the amount ofreformation material supplied, or to the volume of the heat exchangereformer unit.

As described above, with the heat exchange reformer unit according tothis aspect, it is possible to increase reforming efficiency. Thereforming section may be a reaction section for producing reformate gasthat contains hydrogen from supplied reformation material throughreforming reactions including the steam-reforming reaction, for example.

A heat exchange reformer according to a third aspect of the presentinvention includes: a plurality of reforming sections for producingreformate gas, in which reforming catalyst for inducing reformingreactions is supported; and a plurality of heating sections, in whichreforming catalyst for catalytic combustion is supported, for supplyingheat, which is generated by catalytically burning supplied fuel, to thereforming reactions, wherein the plurality of the reforming sections andthe plurality of the heating sections are stacked so that the surfacearea of the region in which the reforming catalyst is supported isgreater than the surface area of the region in which the oxidizingcatalyst is supported.

In the heat exchange reformer unit according to this aspect, reformategas is obtained by bringing supplied reformation material into contactwith the reforming catalyst in the reforming section with combustionheat supplied from the heating section to cause (promote) reformationreactions. In the heat exchange reformer unit according to this aspect,in the area in which heat is exchanged between the reforming sectionsand the heating sections, the surface area of the region in which thereforming catalyst is supported is greater than the surface area of theregion in which the oxidizing catalyst is supported. For this reason,the amount of reforming reaction relative to the amount of combustionreaction is increased, and therefore, the difference in the amount ofreaction between the reforming sections and the combustion sections isreduced (the difference in the amount of reaction per volume iscompensated). That is, the amount of reaction is set according to thereaction field, and it is possible to increase the amount of reformatsgas produced relative to the amount of reformation material supplied, orto the volume of the heat exchange reformer unit.

As described above, with the heat exchange reformer unit according tothis aspect, it is possible to increase reforming efficiency. Thereforming section may be a reaction section for producing reformate gasthat contains hydrogen from supplied reformation material throughreforming reactions including the steam-reforming reaction, for example.

A heat exchange reformer according to a fourth aspect of the presentinvention includes: a plurality of reforming sections for producingreformate gas, in which reforming catalyst for inducing reformingreactions is supported; and a plurality of heating sections, in whichreforming catalyst for catalytic combustion is supported, for supplyingheat, which is generated by catalytically burning supplied fuel, to thereforming reactions, wherein the plurality of the reforming sections andthe plurality of the heating sections are stacked so that the amount ofthe reforming catalyst supported is greater than the amount of theoxidizing catalyst supported.

In the heat exchange reformer unit according to this aspect, reformategas is obtained by bringing supplied reformation material into contactwith the reforming catalyst in the reforming section with combustionheat supplied from the heating section to cause (promote) reformationreactions. In the heat exchange reformer unit according to this aspect,in the area in which heat is exchanged between the reforming sectionsand the heating sections, the amount of reforming catalyst supported isgreater than the amount of oxidizing catalyst supported. For thisreason, the amount of reforming reaction relative to the amount ofcombustion reaction is increased, and therefore, the difference in theamount of reaction between the reforming sections and the combustionsections is reduced (the difference in the amount of reaction per volumeis compensated). That is, the amount of reaction is set according to thereaction field, and it is possible to increase the amount of reformategas produced relative to the amount of reformation material supplied, orto the volume of the heat exchange reformer unit.

As described above, with the heat exchange reformer unit according tothis aspect, it is possible to increase reforming efficiency. Thereforming section may be a reaction section for producing reformats gasthat contains hydrogen from supplied reformation material throughreforming reactions including the steam-reforming reaction, for example.

A heat exchange reformer according to a fifth aspect of the presentinvention includes: a plurality of reforming sections for producingreformate gas, in which reforming catalyst for inducing reformingreactions is supported; and a plurality of heating sections, in whichreforming catalyst for catalytic combustion is supported, for supplyingheat, which is generated by catalytically burning supplied fuel, to thereforming reactions, wherein the plurality of the reforming sections andthe plurality of the heating sections are stacked so that the totalvolume of the plurality of the reforming sections is greater than thetotal volume of the plurality of heating sections.

In the heat exchange reformer unit according to this aspect, reformategas is obtained by bringing supplied reformation material into contactwith the reforming catalyst in the reforming section with combustionheat supplied from the heating section to cause (promote) reformationreactions. In the meantime, because the reaction velocity of reformingreactions is lower than that of combustion reactions, reformingreactions require a reaction space (volume) larger than that ofcombustion reactions. In the heat exchange reformer unit according tothis aspect, in the area in which heat is exchanged between thereforming sections and the heating sections, the total volume of theplurality of the reforming sections (volume, that is, passage crosssection×passage length×number of layers) is greater than the totalvolume of the plurality of the combustion sections. For this reason, thedifference in the amount of reaction per volume between the reformingpassages and the combustion passages is compensated by the difference inthe volume of the respective reaction spaces (volume ratio). That is,the amount of reaction is set according to the reaction field, and it ispossible to increase the amount of reformate gas produced relative tothe amount of reformation material supplied, or to the volume of theheat exchange reformer unit.

As described above, with the heat exchange reformer unit according tothis aspect, it is possible to increase reforming efficiency. Thereforming section may be a reaction section for producing reformats gasthat contains hydrogen from supplied reformation material throughreforming reactions including the steam-reforming reaction, for example.

In the heat exchange reformer unit according to this aspect, the heatexchange reformer unit may include a part in which two layers of thereforming sections are stacked per one layer of the heating section.

The heat exchange reformer unit according to this aspect includes a partin which the reforming sections and the heating sections are stacked sothat the units are stacked in each of which two layers of the reformingsections are disposed on the same side of one layer of the heatingsection, or so that the units are stacked in each of which one layer ofthe heating section is sandwiched between a pair of layers of thereforming sections, for example. In such a part, two layers of thereforming sections are disposed between a pair of the heating sections.Specifically, in the part in which two layers of the reforming sectionsare stacked per one layer of the heating section, at least one side ofeach reforming section is adjacent to a heating section. In this way, itis possible to increase the volume of the reforming sections (thecatalyst-supporting region surface area, or the amount of catalystsupported) with the heat transport distance between the heating sectionsand the reforming sections kept short as compared to that of theconfiguration in which the heating sections and the reforming sectionsare alternately stacked. For example, while the ratio of the volume ofthe reforming sections to the overall volume of the reformer unit isabout 50% in the configuration in which the heating sections and thereforming sections are alternately stacked, it is possible to increasethe ratio of the volume of the reforming sections to the overall volumeof the reformer unit to about 67% in the above configuration.

In the heat exchange reformer unit according to this aspect, the heatexchange reformer unit may include a part in which three layers of thereforming sections are stacked per one layer of the heating section.

The heat exchange reformer unit according to this aspect includes a partin which the reforming sections and the heating sections are stacked sothat the units are stacked in each of which three layers of thereforming sections are disposed on the same side of one layer of theheating section, for example. In such a part, three layers of thereforming sections are disposed between a pair of the heating sections.In this way, while the ratio of the volume of the reforming sections tothe overall volume of the reformer unit is about 50% in theconfiguration in which the heating sections and the reforming sectionsare alternately stacked, for example, it is possible to increase theratio of the volume of the reforming sections to the overall volume ofthe reformer unit to about 75% in the above configuration. It has beenconfirmed that, in this configuration, while a reforming section isformed that is not adjacent to any heating sections (the heat transportdistance is long), the effect caused by the increase in the reactionspace surpasses the effect caused by the increase in the heat transportdistance under the operating conditions in which the operatingtemperature is low, for example.

In the heat exchange reformer unit according to this aspect, the heatexchange reformer unit may include a part in which four or more layersof the reforming sections are stacked per one layer of the heatingsection.

The heat exchange reformer unit according to this aspect includes a partin which the reforming sections and the heating sections are stacked sothat the units are stacked in each of which four layers of the reformingsections are disposed on the same side of one layer of the heatingsection, for example. In such a part, four layers of the reformingsections are disposed between a pair of the heating sections. In thisway, while the ratio of the volume of the reforming sections to theoverall volume of the reformer unit is about 50% in the configuration inwhich the heating sections and the reforming sections are alternatelystacked, for example, it is possible to increase the ratio of the volumeof the reforming sections to the overall volume of the reformer unit toabout 80% or more in the above configuration. It has been confirmedthat, in this configuration, while a reforming section is formed that isnot adjacent to any heating sections (the heat transport distance islong), the effect caused by the increase in the reaction space surpassesthe effect caused by the increase in the heat transport distance underthe operating conditions in which the operating temperature is low, forexample.

The heat exchange reformer unit according to this aspect may furtherinclude a heat transfer-promoting portion for promoting heat transferfrom the heating section to the adjacent reforming section.

In the heat exchange reformer unit according to the above aspect,thermal resistance between the heating sections and the reformingsections is reduced by the heat transfer-promoting portions, whereby theheat transport from the heating section to the reforming section ispromoted. Thus, even in the case of the configuration in which the heattransport distance from part of the reforming sections is long (theconfiguration in which heat transfer-controlled effect is feared), suchas in the case of the configuration in which three reforming sectionsper heating section are provided or four or more reforming sections perheating section are provided, for example, it is possible to efficientlysupply heat to the reforming sections to which the heat transportdistance is long. That is, it is possible to broaden the operatingconditions (the range thereof) in which it is possible to enhance thereforming efficiency using the configuration in which three reformingsections per heating section are provided or four or more reformingsections per heating section are provided. As the heattransfer-promoting portion, a connecting wall or the like connectingbetween the separation walls each separating the reforming section andthe heating section may be used, for example.

A reformer system according to a sixth aspect of the present inventionincludes: the heat exchange reformer unit according to the above aspect;and a water supply system for supplying water to the reforming sectionof the heat exchange reformer unit.

In the reformer system according to this aspect, the water supplied tothe reforming section through the water supply system reacts with thereformation material in the reforming section, and reforms thereformation material into reformate gas that contains hydrogen.Specifically, reforming reactions including the steam-reformingreaction, which is endothermic reaction, occur in the reformingsections, and the heat required to cause the steam-reforming reaction issupplied from the heating sections to the reforming sections. Becausethe reformer system includes the heat exchange reformer unit accordingto the above aspect, the difference in the amount of reaction per volumebetween the reforming passages (reforming sections) and the combustionpassages (heating sections) is compensated, and the reformer systemincreases the amount of reformate gas produced relative to the amount ofreformation material supplied, or to the volume of the heat exchangereformer unit, despite the configuration in which steam-reformingreaction is caused that has reaction velocities lower than those ofcombustion reactions.

The heat exchange reformer unit and the reformer system according to theabove aspects of the present invention have excellent efficiency of heatexchange between the heating sections and the reforming sections, andexhibit the advantageous effect that the reforming efficiency isenhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of theinvention will become apparent from the following description ofpreferred embodiments with reference to the accompanying drawings,wherein like numerals are used to represent like elements and wherein:

FIG. 1 is a schematic system flow diagram of a fuel cell system in whicha heat exchange reformer unit according to any one of first to sixthembodiments of the present invention is used;

FIG. 2 is an exploded perspective view showing a main part of the heatexchange reformer unit according to the first embodiment of the presentinvention;

FIG. 3 is a perspective view of the heat exchange reformer unitaccording to the first embodiment of the present invention;

FIG. 4 is an exploded perspective view showing a catalyst-supportingregion of the heat exchange reformer unit according to the firstembodiment of the present invention;

FIGS. 5A to 5C are diagrams showing a process in which catalyst issupported, in the heat exchange reformer unit according to the firstembodiment of the present invention, wherein FIG. 5A is a schematicdiagram showing a state in which a catalyst carrier is flowing into theheat exchange reformer unit, FIG. 5B is a schematic diagram showing astate in which the inflow of the catalyst carrier is stopped, and FIG.5C is a schematic diagram showing a state in which the catalyst isintroduced;

FIG. 6 is a diagram showing a temperature distribution in a combustionpassage of the heat exchange reformer unit according to the firstembodiment of the present invention;

FIGS. 7A to 7C are schematic diagrams showing examples that aredefective in supporting the catalyst;

FIGS. 8A and 8B are diagrams showing the heat exchange reformer unitaccording to the second embodiment of the present invention, whereinFIG. 8A is a front view, and FIG. 8B is a partially enlarged front view;

FIG. 9 is an exploded perspective view showing a main part of the heatexchange reformer unit according to the second embodiment of the presentinvention;

FIG. 10 is a perspective view showing an external appearance of the heatexchange reformer unit according to the second embodiment of the presentinvention;

FIG. 11 is a diagram schematically showing the reaction field ofreforming reactions and the reaction field of combustion reactions inthe heat exchange reformer unit according to the second embodiment ofthe present invention;

FIG. 12 is a graph showing the ratio of the volume of the reformingpassages to the volume of a multilayer core unit constituting the heatexchange reformer unit according to any one of the embodiments of thepresent invention;

FIG. 13 is a graph showing the relation between the area of the regionin which oxidizing catalyst is supported and the area of the region inwhich reforming catalyst is supported in the multilayer core unitconstituting the heat exchange reformer unit according to any one of theembodiments of the present invention;

FIG. 14 is a diagram showing actually measured values of the conversionratio of the reformation material versus the ratio of the volume of thereforming passages to the volume of the multilayer core unit of the heatexchange reformer unit according to any one of the embodiments of thepresent invention;

FIGS. 15A and 15B are diagrams showing the heat exchange reformer unitaccording to the third embodiment of the present invention, wherein FIG.15A is a front view, and FIG. 15B is a partially enlarged front view;

FIGS. 16A and 16B are diagrams showing the heat exchange reformer unitaccording to the fourth embodiment of the present invention, whereinFIG. 16A is a front view, and FIG. 16B is a plan view;

FIG. 17 is a schematic diagram in which the multilayer core unitconstituting the heat exchange reformer unit according to the fourthembodiment of the present invention is modeled as a heat transfer finunit;

FIG. 18 is a graph showing fin efficiency of the multilayer core unit ofthe heat exchange reformer unit according to any one of embodiments ofthe present invention;

FIGS. 19A and 19B are diagrams showing the heat exchange reformer unitaccording to the fifth embodiment of the present invention, wherein FIG.19A is a front view, and FIG. 19B is a plan view;

FIG. 20 is a front view showing the heat exchange reformer unitaccording to the sixth embodiment of the present invention;

FIGS. 21A and 21B are diagrams showing the heat exchange reformer unitaccording to the seventh embodiment of the present invention, whereinFIG. 21A is a front view, and FIG. 21B is a partially enlarged frontview; and

FIGS. 22A and 22B are diagrams showing the heat exchange reformer unitaccording to a comparative example for comparison with the embodimentsof the present invention, wherein FIG. 22A is a front view, and FIG. 22Bis a partially enlarged front view;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A heat exchange reformer unit 10 according to a first embodiment of thepresent invention will be described with reference to FIGS. 1 to 6.First, the overall system configuration of a fuel cell system 11, inwhich the heat exchange reformer unit 10 is used, will be described, andthen the structural details of the heat exchange reformer unit 10 willbe described.

FIG. 1 shows a system configuration diagram (process flow sheet) of thefuel cell system 11. As shown in FIG. 1, the fuel cell system 11 isconstructed using, as main components, a fuel cell 12 that uses hydrogento generate electricity, and the heat exchange reformer unit (reformer)10 for producing reformate gas that contains hydrogen to be supplied tothe fuel cell 12.

The fuel cell 12 is constructed with electrolyte (not shown) interposedbetween an anode electrode (fuel electrode) 14 and a cathode electrode(air electrode) 16, and is configured so as to generate electricitymainly by electrochemically reacting the hydrogen that is supplied tothe anode electrode 14, and the oxygen that is supplied to the cathodeelectrode 16. Although various types of fuel cells may be used as thefuel cell 12, in this embodiment, a fuel cell having proton conductiveelectrolyte (such as a solid polymer fuel cell and a hydrogen membranefuel cell) is used, which is operated at medium temperatures (about 300to 700° C.), and in which water is produced at the cathode electrode 16as electricity is generated.

As shown in FIG. 1, the heat exchange reformer unit 10 includes: areforming passage 18, which constitutes a reforming section forproducing the reformate gas, which contains hydrogen, to be supplied tothe anode electrode 14 of the fuel cell 12; and a combustion passage 20,which constitutes a heating section for supplying heat that is used inthe reforming passage 18 to cause reforming reactions. The reformingpassage 18 supports reforming catalyst 22, so that reformate gas thatcontains hydrogen is produced (reforming reactions are caused) bycatalytically reacting hydrocarbon gas (such as gasoline, methanol andnatural gas) and reforming gas (steam), which are supplied.

The reforming reactions in the reforming passage 18 includes reactionsincluding the steam-reforming reaction expressed by the equation (1), asshown by the following equations (1) to (4). Accordingly, the reformategas obtained through the reforming process contains combustible gas,such as hydrogen (H₂), carbon monoxide (CO), methane (CH₄), decomposedhydrocarbon and unreacted hydrocarbon material (C_(x)H_(y)), andincombustible gas, such as carbon dioxide (CO₂) and water (H₂O).

C_(n)H_(m) +nH₂O?nCO+(n+m/2)H₂  (1)

C_(n)H_(m) +n/2O₂ ?nCO+m/2H₂  (2)

CO+H₂O

CO₂+H₂  (3)

CO+3H₂?CH₄+H₂O  (4)

The steam-reforming reaction expressed by the equation (1), which is theprincipal reaction among these reforming reactions, is endothermicreaction, and, in the reforming passage 18, operation is performed attemperatures equal to or higher than a predetermined temperature tosupply reformate gas to the fuel cell 12 that is operated at medium orhigh temperatures as described above. The combustion passage 20 isconfigured so as to supply heat used to maintain the reforming reactionsand the working temperature in the reforming passage 18. The combustionpassage 20 supports oxidizing catalyst 24, and is disposed adjacent tothe reforming passage 18, so that the combustion passage 20 isconfigured so as to bring the supplied fuel and oxygen into contact withthe oxidizing catalyst 24 to cause catalytic combustion. The partialoxidation reaction expressed by the equation (2) is exothermic reaction.The heat generated by the partial oxidation reaction is used in thesteam-reforming reaction together with the heat supplied from thecombustion passage 20.

The heat exchange reformer unit 10 is designed to supply the combustionheat obtained by catalytically burning fuel in the combustion passage 20to the reforming passage 18 through a plate portion 52 described later.Thus, the heat exchange reformer unit 10 is configured so as to be ableto directly supply heat to the reforming passage 18 without convertingthe heat into temperature as in the case of the configuration in whichthe reforming passage 18 is heated using heating medium (fluid), such ascombustion gas.

The fuel cell system 11 includes a material pump 26 for supplyinghydrocarbon material to the reforming passage 18. The discharge port ofthe material pump 26 is connected to a material inlet port 18A of thereforming passage 18 through a material supply line 28. The hydrocarbonmaterial includes a very small amount of sulfur ingredients (sulfurcompounds), which do not contribute to the reforming reactions describedabove. The hydrocarbon material is supplied to the reforming passage 18in a gas phase or in an atomized form by a vaporizing device or the like(not shown), such as a vaporizer and an injector.

A reformate gas outlet 18B of the reforming passage 18 is connected tothe upstream end of a reformate gas supply line 30, the downstream endof which is connected to a fuel inlet 14A of the anode electrode 14.Thus, the reformate gas produced in the reforming passage 18 is suppliedto the anode electrode 14 of the fuel cell 12. The upstream end of ananode off-gas line 32 is connected to an off-gas outlet 14B of the anodeelectrode 14. The downstream end of the anode off-gas line 32 isconnected to a fuel inlet 33A of a gas mixer 33. The gas mixer 33substantially homogeneously mixes the anode off-gas and the coolantoff-gas supplied through a combustion-supporting gas supply line 46described later. A mixed gas outlet 33B of the gas mixer 33 is connectedto a fuel (mixed gas) inlet 20A of the fuel passage 20.

In this way, the fuel cell system 11 is designed so that hydrogen in thereformate gas produced in the reforming passage 18 is used in the fuelcell 12, the remaining components, other than the used hydrogen, areintroduced into the combustion passage 20 as an anode off-gas, and thecombustible components therein (H₂, CO, HC and CH₄) are used as fuel inthe combustion passage 20. An exhaust gas line 34 for dischargingcombustion exhaust gas out of the system is connected to an exhaust gasoutlet 20B.

The fuel cell system 11 includes a cathode air pump 36 for supplyingcathode air to the cathode electrode 16. Connected to the discharge portof the cathode air pump 36 is the upstream end of a cathode air supplyline 38, the downstream end of which is connected to an air inlet 16A ofthe cathode electrode 16. The upstream end of a steam supply line 40 isconnected to an off-gas outlet 16B of the cathode electrode 16, and thedownstream end of the steam supply line 40 is connected to a steam inlet18C of the reforming passage 18. Thus, the cathode off-gas that containssteam produced by the cathode electrode 16 and oxygen that is not usedon the cathode electrode 16 are supplied to the reforming passage 18.The steam in the cathode off-gas is used in the steam-reforming reactionexpressed by the equation (1), and oxygen is used in the partialoxidation reaction expressed by the equation (2). The heat exchangereformer unit 10 according to the first embodiment is configured so asto be operated under particular conditions in which the O/C ratio thatis the ratio of the amount of supplied oxygen to the amount of carbon inthe hydrocarbon material is set to a particular ratio by supplyingcathode off-gas that contains oxygen to the reforming passage 18.

The fuel cell system 11 includes a cooling air pump 42 for supplyingcooling air to the fuel cell 12. The discharge port of the cooling airpump 42 is connected to the upstream end of a cooling air supply line44, the downstream end of which is connected to an inlet 12A of thecoolant passage (not shown) of the fuel cell 12. An outlet 12B of thecoolant passage is connected to the upstream end of acombustion-supporting gas supply line 46. The combustion-supporting gassupply line 46 is connected to a combustion-supporting gas inlet 33C ofthe gas mixer 33 so as to supply coolant off-gas that contains oxygen ascombustion-supporting gas to the gas mixer 33. Thus, in the combustionpassage 20, the mixed gas that is obtained by mixing the anode off-gassupplied through the anode off-gas line 32 and the coolant off-gassupplied through the combustion-supporting gas supply line 46 in the gasmixer 33, is brought into contact with the oxidizing catalyst 24 thatthe combustion passage 20 has therein, thereby causing catalyticcombustion. It should be noted that, instead of the configuration inwhich the gas mixer 33 is provided, a configuration may be adopted inwhich the downstream end of the anode off-gas line 32 and the downstreamend of the combustion-supporting gas supply line 46 are individuallyconnected to the combustion passage 20, for example.

In the above configuration, the fuel cell 12 (cathode electrode 16) andthe steam supply line 40 may be regarded as the water supply device ofthe present invention, and the fuel cell system 11 (more specifically,the part of the fuel cell system 11, which includes the heat exchangereformer unit 10, the cathode electrode 16, and the steam supply line40) may be regarded as the reformer system of the present invention.

With regard to the fuel cell system 11, a configuration may be adoptedin which the steam supply line 40 is provided with a separation membrane(a porous separation membrane made of polyimide and ceramic, forexample) that selectively allows permeation of only the steam in thecathode off-gas, or in which the steam used in reforming is introducedfrom the outside of the system, so that oxygen is not supplied to thereforming passage 18, or that the ratio (O/C ratio) of the amount ofsupplied oxygen to the amount of carbon in the hydrocarbon material issmall. In the case of such configurations, the main reaction of thereforming reactions in the heat exchange reformer unit 10 is thesteam-reforming reaction, and therefore, the partial oxidation reactionis not caused, or the amount of heat generated by the partial oxidationreaction becomes very small.

FIG. 2 shows a multilayer core unit 65 of the heat exchange reformerunit 10 in an exploded perspective view. As shown in FIG. 2, in the heatexchange reformer unit 10, the reforming passages 18 constituting thereforming sections and the combustion passages 20 constituting theheating sections are formed in the form of separate gas passages betweenthe unit plate members 50 and 51, which are provided as a plurality ofreforming section-forming plate members and a plurality of heatingsection-forming plate members, which are stacked, wherein the reformingpassages 18 and the combustion passages 20 are separated by the plateportions 52 as separation walls, which may be regarded as flat-shapedplate portions of the unit plate members 50 and 51. In this embodiment,the reforming passages 18 and the combustion passages 20 are alternatelystacked in the stacking direction (the thickness direction of the plateportion 52). The reforming passage 18 and the combustion passage 20 areadjacent to each other with the plate portion 52 interposedtherebetween. Specific description will be given below.

The unit plate member 50 includes the plate portion 52 formed in a flatshape. The plate portion 52 is formed by integrally providing, at bothends in the longitudinal direction of a parallel flow portion 52constituting a heat exchanging section formed in a rectangular shape,flow direction-changing sections 52B and 52C, when viewed from above. Inthis embodiment, the flow direction-changing sections 52B and 52C areformed in a triangular shape such that the bases thereof are made tocoincide with the corresponding short sides of the parallel flow portion52A (with a rectangular shape). Accordingly, the plate portion 52 as awhole is formed in a substantially hexagonal shape. Each unit platemember 50 includes outer walls 54, which are provided in a standingcondition at edges of the plate portion 52 on the side thereof on whichthe reforming passages 18 are formed.

The outer walls 54 are provided in a standing condition all around theplate portion 52 except one side portion of each of thedirection-changing sections 52B and 52C, so that the outer walls 54function as spacers that define the reforming passages 18 between thestacked unit plate members 50 and 51, and also function as outer wallsthat prevent the outflow of gas from the reforming passages 18, and, atthe same time, create a gas inlet 50A on the flow-direction changingsection 52B-side, and a gas outlet 50B on the flow-direction changingsection 52C-side. The gas inlet 50A and the gas outlet 50B are formedsymmetrically with respect to the centroid of the plate portion 52, andthe openings thereof are oriented in the directions indicated by thearrows C1 and C2 beside the flow-direction changing sections 52B and52C, respectively, which are opposite to the direction of the parallelflow portion 52A, which extends along the longitudinal direction of theouter walls 54.

A plurality of standing walls (partition walls) 56 that divide thereforming passage 18 into a plurality of parallel passages are providedin a standing condition on the reforming passage 18-formed-side of theplate portion 52 of the unit plate members 50. The standing walls 56 aremade substantially parallel with the outer walls 54 from the gas inlet50A to the gas outlet 50B, and are configured so as to divide thereforming passage 18 into a plurality of divided passages(microchannels) 58. Each divided passage 58 is formed in a crank-likeshape such that the length of the passages from the gas inlet 50A to thegas outlet 50B is substantially the same owing to the symmetricalarrangement of the gas inlet 50A and the gas outlet 50B described above.

The part of the divided passages 58 in the parallel flow portion 52Athat are separated by partition wall portions 56A of the standing walls56 lying along the longitudinal direction of the parallel flow portions52A, serve as heat-exchanging passages 58A. Meanwhile, the part of thedivided passages 58 between which inlet guide walls 56B are provided onthe flow-direction changing section 52B in a standing condition, serveas reformation material guide passages 58B constituting a reformationmaterial guide section. The inlet guide walls 56B are part of thestanding walls 56, and lie along the direction indicated by the arrowC1. In addition, the part of the divided passages 58 between whichoutlet guide walls 56C are provided on the flow-direction changingsection 52C in a standing condition, serve as reformate gas guidepassages 58C constituting a reformate gas guide section. The outletguide walls 56C are part of the standing walls 56, and lie along thedirection indicated by the arrow C2.

The unit plate member 51 includes a plate portion 52 that has the sameshape as that of the plate portion 52 constituting the unit plate member50, and includes outer walls 60, which are provided in a standingcondition at the periphery of the plate portion 52 on the side thereofon which the combustion passages 20 are formed. The outer walls 60 areprovided in a standing condition all around the plate portion 52 exceptone side portion of each of the direction-changing sections 52B and 52C,so that the outer walls 60 function as spacers that form the combustionpassages 20 between the stacked unit plate members 50 and 51, and alsofunction as outer walls that prevent the outflow of gas from thecombustion passages 20, and so that the outer walls 60 form a gas inlet51A on the flow-direction changing section 52B-side, and a gas outlet51B on the flow-direction changing section 52C-side.

The gas inlet 51A is formed on the same side of a parallel flow portion52A in the longitudinal direction as the gas inlet 50A of the unit platemember 50 (that is, on the side indicated by the arrow A in FIG. 2) soas to be open toward the direction indicated by the arrow D1, which isdifferent from the direction indicated by the arrow C1 (that is, whichis symmetric with respect to the longitudinal axis of the parallel flowportion 52A), toward which the gas inlet 50A is open. Meanwhile, the gasoutlet 5B is formed on the same side of a parallel flow portion 52A inthe longitudinal direction as the gas outlet 50B of the unit platemember 50 (that is, on the side indicated by the arrow B in FIG. 2) soas to be open toward the direction indicated by the arrow D2, which isdifferent from the direction indicated by the arrow C2 (that is, whichis symmetric with respect to the longitudinal axis of the parallel flowportion 52A), toward which the gas outlet SOB is open.

A plurality of standing walls (partition walls) 62 that divide thecombustion passage 20 into a plurality of parallel passages are providedin a standing condition on the combustion passage 20-formed-side of theplate portion 52 of the unit plate members 51. The standing walls 62 aremade substantially parallel with the outer walls 60 from the gas inlet51A to the gas outlet 51B, and are configured so as to divide thecombustion passage 20 into a plurality of divided passages(microchannels) 64. Each divided passage 64 is formed in a crank-likeshape such that the length of the passages from the gas inlet 51A to thegas outlet 51B is substantially the same owing to the symmetricalarrangement of the gas inlet 51A and the gas outlet 51B described above.

The part of the divided passages 64 in the parallel flow portion 52Athat are separated by partition wall portions 62A of the standing walls62 lying along the longitudinal direction of the parallel flow portions52A, serve as heat-exchanging passages 64A. Meanwhile, the part of thedivided passages 64 between which inlet guide walls 62B are provided onthe flow-direction changing section 52B in a standing condition, serveas mixed gas guide passages 64B constituting a fuel guide section. Theinlet guide walls 62B are part of the standing walls 62, and lie alongthe direction indicated by the arrow D1. In addition, the part of thedivided passages 64 between which outlet guide walls 62C are provided onthe flow-direction changing section 52C in a standing condition, serveas combustion exhaust gas guide passages 64C constituting a combustionexhaust gas guide section. The outlet guide walls 62C are part of thestanding walls 62, and lie along the direction indicated by the arrowD2.

In the heat exchange reformer unit 10 described above, the gas inlets50A and 51A are positioned on the same side (that is, on the sideindicated by the arrow A) of the parallel flow portion 52A (theheat-exchanging passages 58A and 64A), and the gas outlets SOB and SIBare positioned on the same side (that is, on the side indicated by thearrow B) of the parallel flow portion 52A as described above, so thatthe directions in which gas flows in the heat-exchanging passages 58Aand 64A on the respective layers are set to the same direction (thedirection indicated by the arrow F).

In each of the unit plate members 50 and 51 described above, theportions (the plate portion 52, the outer walls 54 and the standingwalls 56; or the plate portion 52, the outer walls 60 and the standingwalls 62) are integrally formed of metallic materials, such as stainlesssteel, or solid (not porous) ceramics, for example. The plurality of theunit plate members 50 and the plurality of the unit plate members 51constitute the multilayer core unit 65 of the heat exchange reformerunit 10, wherein the plate members 52 and the outer walls 54 and 60 (thestanding walls 56 and 62) are airtightly joined by brazing using brazingfiller or by diffusion bonding, for example. As shown in FIG. 3, in theheat exchange reformer unit 10, in this embodiment, a flat-shaped plateportion 52 (cover) on which the outer walls 54 or the like are notprovided in a standing condition is placed on the top of the heatexchange reformer unit 10 so as to close the reforming passage 18.

As shown in FIG. 3, a reformation inlet manifold 66 that defines acollection space to which the gas inlets 50A of the respective layersare open is connected to the multilayer core unit 65. In addition, areformation outlet manifold 68 that defines a collection space to whichthe gas outlets 50B of the respective layers are open is connected tothe multilayer core unit 65. Moreover, a combustion inlet manifold 70that defines a collection space to which the gas inlets 51A of therespective layers are open is connected to the multilayer core unit 65.Furthermore, a combustion outlet manifold 72 that defines a collectionspace to which the gas outlets 51B of the respective layers are open isconnected to the multilayer core unit 65. Bach of the manifolds 66, 68,70 and 72 is formed in a rectangular tube shape, and one open endthereof is joined to the end portions of the top and bottom plateportions 52, and the end portions of the outer walls 54 and 60 of therespective layers by brazing, for example.

The material inlet 18A and the steam inlet 18C for introducingreformation material (hydrocarbon) and steam (cathode off-gas),respectively, are provided in the reformation inlet manifold 66, and thereformats gas outlet 18B for discharging reformate gas is provided inthe reformation outlet manifold 68. Meanwhile, the fuel inlet 20A forintroducing mixed gas from the gas mixer 33 is provided in thecombustion inlet manifold 70, and the exhaust gas outlet 20B fordischarging combustion exhaust gas is provided in the combustion outletmanifold 72.

In the heat exchange reformer unit 10 (multilayer core unit 65)described above, the reforming catalyst 22 is supported on the innersurface of the divided passages 58 on the unit plate member 50, and theoxidizing catalyst 24 is supported on the inner surface of the dividedpassages 64 on the unit plate member 51. As shown in FIG. 4, which is anexploded plan view in which the illustration of the standing walls 56and 62 is omitted, the reforming catalyst 22 is supported in the dividedpassages 58 (reforming passage 18) in a predetermined region thereofthat does not include part of the divided passages 58 on the gas inlet50A-side, and the oxidizing catalyst 24 is supported in the dividedpassages 58 (combustion passage 20) in a predetermined region thereofthat does not include part of the divided passages 64 on the gas inlet51A-side.

More specifically, as shown in FIG. 4, with regard to the reformingcatalyst 22, an upstream-side supporting region end 22A that is the endon the upstream side (that is, on the side indicated by the arrow A) inthe gas flow direction in which the reformation material is supplied,substantially coincides with the border between the heat-exchangingpassages 58A (parallel flow sections 52A) and the reformation materialguide passages 58B (flow direction-changing sections 521) of the dividedpassages 58. With regard to the oxidizing catalyst 24, an upstream-sidesupporting region end 24A that is the end on the upstream side (that is,on the side indicated by the arrow A) in the gas flow direction in whichthe fuel is supplied, substantially coincides with the border betweenthe heat-exchanging passages 64A (parallel flow sections 52A) and themixed gas guide passages 64B (flow-direction changing sections 52B) ofthe divided passages 64. It should be noted that the upstream-sidesupporting region end 24A of the oxidizing catalyst 24 coincides withthe upstream-side supporting region end 22A of the reforming catalyst22, or is positioned a bit further downstream than the upstream-sidesupporting region end 22A.

With regard to the heat exchange reformer unit 10, as shown in FIGS. 5Aand 5B, a catalyst carrier is applied on the divided passages 58 of thereforming passage 18 and the divided passages 64 of the combustionpassage 20 by immersing the multilayer core unit 65, from the endthereof on the gas outlet 50B-side, or 51B-side, into a slurry-likecatalyst carrier 75 stored in a storage tank 76. Then, the catalystcarrier 75 applied on the divided passages 58 and 64 is caused tosupport the reforming catalyst 22 and the oxidizing catalyst 24,respectively. In order to stop the catalyst carrier at the upstream-sidesupporting region ends 22A and 24A (control line), the detection signalfrom a catalyst sensor or sensors 74 for detecting the catalyst carrier,which are provided in representative ones of or all of the dividedpassages 58 and 64, is used. A method of producing the heat exchangereformer unit 10 will be specifically described below.

When the heat exchange reformer unit 10 is produced, as shown in FIG. 3,the unit plate members 50 and 51 are alternately stacked, and the freeedges of the outer walls 54 and 60 are bonded to the plate portions 52of the adjacent unit plate members 51 and 50, respectively. Thus, themultilayer core unit 65 is formed. Next, as shown in FIG. 5A, thecatalyst-supporting region position sensors 74 are set on the dividedpassages 58 and 64 of the multilayer core unit 65. Thecatalyst-supporting region position sensor 74 is designed to output anON signal to a notification device (not shown), such as a display deviceand notification sound-generating device, when the catalyst carrier isbrought into contact with a slurry-detecting portion 74A provided on thetip of the sensor. Thus, the catalyst-supporting region position sensors74 are inserted into representative ones of the divided passages 58 and64 from the gas inlet 50A-side, or 51A-side so that the slurry-detectingportions 74A are positioned at the desired positions to which theupstream-side supporting region end 22A of the reforming catalyst 22 andthe upstream-side supporting region end 24A of the oxidizing catalyst 24on the divided passages 58 and 64 are controlled.

The multilayer core unit 65 in which the catalyst-supporting regionposition sensors 74 are set is immersed into the catalyst carrier 75 inthe storage tank 76 from the gas outlet-SOB, or 51B-side. Inconsideration of the fact that, in the multilayer core unit 65 having amicrochannel structure, the level of the surface of the catalyst carrier75 in the divided passages 58 and 64 becomes higher than the levelthereof in the storage tank 76 due to the capillary phenomenon, themultilayer core unit 65 is gradually (slowly) immersed into the catalystcarrier 75 until a notification is made by the notification device(until the catalyst-supporting region position sensor(s) 74 detects thecatalyst carrier 75), as shown in FIGS. 5A and 5B. After the activationof the notification device, the multilayer core unit 65 is drawn out ofthe storage tank 76, and the surplus catalyst carrier 75 is removed fromthe divided passages 58 and 64 by blowing air thereinto through the gasinlets 50A and 51A, for example.

Subsequently, as shown in FIG. 5C, the reforming catalyst 22 is suppliedinto the divided passages 58 through the gas outlets 50B to cause thecatalyst carrier 75 in the divided passages 58 to support the reformingcatalyst 22. Then, the oxidizing catalyst 24 is supplied into thedivided passages 64 through the gas outlets 51B to cause the catalystcarrier 75 in the divided passages 64 to support the oxidizing catalyst24. Thus, the multilayer core unit 65 is constructed in which thereforming catalyst 22 is supported in the heat-exchanging passages 58Aand the reformate gas guide passages 58C of the divided passages 58 butis not supported in the reformation material guide passages 58B, and inwhich the oxidizing catalyst 24 is supported in the heat-exchangingpassages 64A and the combustion exhaust gas guide passages 64C of thedivided passages 64 but is not supported in the mixed gas guide passages64B.

Then, the reformation inlet manifold 66, the combustion inlet manifold70, the reformation outlet manifold 68, and the combustion outletmanifold 72 are respectively joined to the opening portions of the gasinlets 50A and 51A, and the gas outlets 50B and 51B of the respectivelayers of the multilayer core unit 65. Thus, the production process ofthe heat exchange reformer unit 10 as shown in FIG. 3 is completed.

Next, operations of the first embodiment will be described.

In the fuel cell system 11 with the above construction, operating thematerial pump 26 and the cathode air pump 36 causes hydrocarbon materialand steam (cathode off-gas) to be introduced into the reforming passages18 of the heat exchange reformer unit 10 through the material supplyline 28. In the reforming passages 18 of the heat exchange reformer unit10, the reforming reactions including the steam-reforming reactionexpressed by the equation (1) and the partial oxidation reactionexpressed by the equation (2) (see the above equations (1) to (4)) arecaused by bringing the introduced hydrocarbon material and steam intocontact with the reforming catalyst 22 with heat supplied from thecombustion passages 20, so that reformate gas that contains hydrogen inhigh concentration is produced.

The reformate gas produced in the reforming passages 18 is supplied tothe anode electrode 14 through the fuel inlet 14A of the anode electrode14. In the fuel cell 12, hydrogen in the reformate gas supplied to theanode electrode 14 is turned into protons, and the protons migrate tothe cathode electrode 16 through the electrolyte to react with oxygen inthe air introduced onto the cathode electrode 16. As the protons migratein this way, electrons flow from the anode electrode 14 toward thecathode electrode 16 through the external conductor, so that electricityis generated.

In the fuel cell 12, the generation of electricity uses hydrogen in thereformate gas supplied to the anode electrode 14 and oxygen in thecathode air supplied to the cathode electrode 16 in accordance with theamount of electricity generated (the electric power consumption of aload), and water (steam under operating temperature conditions) isproduced at the cathode electrode 16. The gas that contains steam isexpelled from the cathode electrode 16 to the steam supply line 40 ascathode off-gas as described above, and introduced into the reformingpassage 18 through the steam inlet 18C.

The gas resulting after hydrogen in the reformate gas is used accordingto the amount of generated electricity as electricity is generated, isdischarged from the anode electrode 14 as anode off-gas. The anodeoff-gas is supplied to the combustion passages 20 of the heat exchangereformer unit 10 through the anode off-gas line 32. In addition, thecoolant off-gas after cooling the fuel cell 12 is supplied to thecombustion passages 20 through the combustion-supporting gas supply line46. In the combustion passages 20, catalytic combustion is caused bybringing the combustible components in the anode off-gas, which is fuel,into contact with the oxidizing catalyst 24 together with the oxygen inthe coolant off-gas as the combustion-supporting gas. The heat producedby the catalytic combustion is supplied to the reforming passages 18through the plate portions 52. Using the heat, in the reforming passages18, the reforming reactions, which are endothermic reactions, aremaintained, and the operating temperature (reformate gas temperature) ismaintained at a temperature required to bring about reforming reactions.

In this way, the fuel cell system 11 supplies hydrocarbon material tothe heat exchange reformer unit 10, and effectively uses various exhaustgases of the fuel cell 12 (the cathode off-gas that contains steam, theanode off-gas that contains combustible components, and the coolantoff-gas that contains oxygen) to maintain the operation of the heatexchange reformer unit 10, which produces hydrogen that is supplied tothe fuel cell 12.

The reforming reactions in the reforming passages 18 have an endothermicpeak on the reformation material inlet side, that is, on theupstream-side catalyst-supporting region 22A-side of the region in whichthe reforming catalyst 22 is supported. The burning reactions in thecombustion passages 20 have an exothermic peak on the fuel inlet side,that is, on the upstream-side catalyst-supporting region 24A-side of theregion in which the reforming catalyst 24 is supported. Thus, incross-flow heat exchange reformer units, for example, the gas flowdirections in a reforming section and a heating section intersect witheach other, and therefore, there is a problem that localhigh-temperature regions occur due to the structure. Meanwhile, incounter-flow heat exchange reformer units, for example, an endothermicpeak and an exothermic peak in a reforming section and a heating sectionoccur at opposite end portions with respect to the gas flow direction ina heat exchanging section, and therefore, counter-flow heat exchangereformer units are not suitable for the heat exchangers in reformers.

With regard to the heat exchange reformer unit 10, a parallel-flow heatexchanger, in which the gas flow direction in the heat-exchangingpassages 58A of the reforming passage 18 and the gas flow direction inthe heat-exchanging passages 64A of the combustion passage 20 are thesame, is constructed, that is, it is possible to set an endothermic peakand an exothermic peak on the same side with respect to the gas flowdirection, wherein, in the reforming reactions, the endothermic peakoccurs on the gas inlet 50A-side to which reformation material issupplied, and, in the combustion reactions, the exothermic peak occurson the gas inlet 51A-side to which fuel is supplied. Accordingly, theefficiency of heat exchange between the reforming passages 18 and thecombustion passages 20 is enhanced. Thus, with the heat exchangereformer unit 10, it is possible to efficiently produce hydrogen byreforming, using heat generated in the combustion passage 20effectively.

Thus, in the heat exchange reformer unit 10 according to the firstembodiment, the efficiency of heat exchange between the combustionpassages 20 and the reforming passages 18 is excellent.

In addition, in the heat exchange reformer unit 10, the reformationmaterial guide passages 58B and the mixed gas guide passages 64B, whichare located on the upstream side of the heat-exchanging passages 58A and64A substantially constituting a parallel-flow heat exchanger,constitute a cross-flow heat exchanging section, so that the heatexchange therein enables stable operation against fluctuation(robustness is enhanced). An experimental example is shown in FIG. 6.FIG. 6 is a diagram showing a temperature distribution at points alongthe gas flow direction in the divided passages 64 when the temperatureof the mixed gas supplied is at a constant temperature of 400° C. Thesolid line represents the case where the temperature of the reformationmaterial supplied to the divided passages 58 is 600° C., and the dashedline represents the case where the temperature of the reformationmaterial supplied to the divided passages 58 is 400° C. From thisfigure, it can be seen that, even when the temperature of the gasflowing into the divided passages 58 varies by 200° C., the increase inthe highest temperature in the divided passages 64 is restricted to 30°C. That is, the heat exchange reformer unit 10 makes it possible toeffectively suppress sharp variation in the temperature of the reactionfield depending on the gas inlet temperature.

In the heat exchange reformer unit 10, the reforming catalyst 22 and theoxidizing catalyst 24 are not supported in the cross-flow heatexchanging section, which is constituted of the reformation materialguide passages 58B and the mixed gas guide passages 64B, and therefore,neither a reforming reaction nor a combustion reaction occurs in thereformation material guide passages 58B and the mixed gas guide passages64B. Accordingly, the occurrence of local high-temperature regions dueto the unbalance between the positions of the endothermic region and theexothermic region is prevented, which is a problem arising when across-flow heat exchange reformer unit is used. Experimental resultshave been obtained that show that, while, in the case where thereforming catalyst 22 and the oxidizing catalyst 24 are supported in thereformation material guide passages 58B and the mixed gas guide passages64B, respectively, the maximum temperature in the reformation materialguide passages 58B is about 800° C. when the temperature of thereformate gas discharged from the divided passages 58 (reformationoutlet manifold 68) is controlled at 650° C., the maximum temperature inthe reformation material guide passages 58B in the heat exchangereformer unit 10 is about 180° C. under the same conditions.

Thus, by providing the cross-flow heat exchanging section(quasi-cross-flow section), which is constituted of the reformationmaterial guide passages 58B and the mixed gas guide passages 64B,upstream of the parallel-flow heat-exchanging section, which isconstituted of the heat-exchanging passages 58A and the heat-exchangingpassages 64A, it is made possible to realize an ideal reaction field(thermal balance) in the reforming passages 18 and the combustionpassages 20, and in addition, the improvement in the robustness of thesystem is achieved.

In addition, because the region in which the catalyst carrier 75 isprovided, that is, the region in which the reforming catalyst 22 and theoxidizing catalyst 24 are supported, is controlled using thecatalyst-supporting region position sensor 74, it is possible toaccurately form the upstream-side supporting region ends 22A and 24A ofthe reforming catalyst 22 and the oxidizing catalyst 24. Specifically,although, with regard to the multilayer core unit 65 in which multipleunit plate members 50 and 51 are stacked, it is infeasible to see theinside of the divided passages 58 and 64, it is possible to prevent thesituation where catalyst is supported in the reformation material guidepassages 58B and the mixed gas guide passages 64B as shown in FIG. 7A,the situation where the amount of catalyst supported in theheat-exchanging passages 58A and 64A is insufficient as shown in FIG.7B, and the situation where the regions in which the reforming catalyst22 and the oxidizing catalyst 24 are supported are significantlydifferent from each other as shown in FIG. 7C, by using thecatalyst-supporting region position sensor 74.

Moreover, in the multilayer core unit 65 of the heat exchange reformerunit 10, the reformation material guide passages 58B and the mixed gasguide passages 64B, which are positioned upstream of the heat-exchangingpassages 58A and 64A substantially constituting a parallel-flow heatexchanger, constitute a cross-flow (quasi-cross-flow) section, so thatit is possible to form the gas inlets 50A, whose surface planes in therespective layers are substantially on the same plane, and the gas inlet51A, whose surface planes in the respective layers are substantially onthe same plane, in the form of separate opening portions that are opentoward different directions. Thus, a construction is realized, in which,while a parallel-flow configuration is adopted that shows an excellentbalance between heat generation and heat absorption as described above,the reformation inlet manifold 66 that defines the collection space towhich the gas inlets 50A of the respective layers are open is connectedto the multilayer core unit 65, and the combustion inlet manifold 70that defines the collection space to which the gas inlets 51A of therespective layers are open is connected to the multilayer core unit 65.Accordingly, it is possible to improve the homogeneity of thedistribution of the amount of gas flowing into the divided passages 58and 64, as compared to the configuration in which reformation materialand mixed gas (anode off-gas as fuel) are supplied to the gas inlets 50Aand 51A of the respective layers individually.

In particular, when the combustion inlet manifold 70 is provided, it ismade possible to dispose the gas mixer 33, which supplies mixed gas tothe divided passages 64 (combustion passages 20), immediately before thegas inlets 51A. When such a gas mixer 33 is structured in the form of amixing space provided downstream of the microchannel structure, which isconstructed by alternately stacking such unit plates as obtained byremoving the flow direction-changing section 52C and the outlet guidewalls 56C or 62C from the unit plate members 50 and 51, it is madepossible to dispose, or form, the gas mixer 33 in the combustion inletmanifold 70 (or in a pipe with a rectangular cross-section connected tothe combustion inlet manifold 70).

In the multilayer core unit 65 of the heat exchange reformer unit 10,the reformate gas guide passages 58C and the combustion exhaust gasguide passages 64C, which are positioned downstream of theheat-exchanging passages 58A and 64A substantially constituting aparallel-flow heat exchanger, constitute a cross-flow (quasi-cross-flow)section, so that it is possible to form the gas outlets 50B and 51B inthe form of separate opening portions that are open toward differentdirections. Thus, a construction is realized, in which, while aparallel-flow configuration is adopted that shows an excellent balancebetween heat generation and heat absorption as described above, thereformation outlet manifold 68 that defines the collection space towhich the gas outlets 50B of the respective layers are open is connectedto the multilayer core unit 65, and the combustion outlet manifold 72that defines the collection space to which the gas outlets 51B of therespective layers are open is connected to the multilayer core unit 65.Accordingly, in cooperation with the effect caused by providing thereformation inlet manifold 66 and the combustion inlet manifold 70described above, it is possible to further improve the homogeneity ofthe distribution of the amount of gas flowing into the divided passages58 and 64, as compared to the configuration in which reformate gas andcombustion exhaust gas are discharged from the gas outlets 50B and 51Bof the respective layers individually.

In addition, in the above embodiments, examples provided with the unitplate members 50 and 51 in each of which the substantiallyrectangular-parallel flow section 52A (the heat-exchanging passages 58Aand 64A) is integrated with the substantially triangular-flowdirection-changing sections 52B and 52C (the gas guide passages 58B and58C, and 64B and 64C) are illustrated. However, the present invention isnot limited to these examples, and the flow direction-changing sections52B and 52C with various shapes may be provided. In addition, theconfiguration of the guide walls 56B and the like that constitute thegas guide passages 58B and the like together with the flowdirection-changing section 52B and the like is not limited to aconfiguration having a straight shape. The guide walls 56B and the likemay have a curved shape, for example.

A heat exchange reformer unit 10 according to a second embodiment of thepresent invention will be described with reference to FIGS. 1, 4 and 8Ato 11. FIG. 8A shows the multilayer core unit 65, which is a maincomponent of the heat exchange reformer unit 10, in a front view insection. FIG. 9 shows the multilayer core unit 65 in an explodedperspective view. As shown in these figures, in the multilayer core unit65 of the heat exchange reformer unit 10, the reforming passages 18 asthe reforming sections, and the combustion passages 20 as the heatingsections are formed in the form of separate gas passages between theunit plate members 50 and 51, which are provided as a plurality ofreforming section-forming plate members and a plurality of heatingsection-forming plate members, which are stacked, wherein the reformingpassages 18 and the combustion passages 20 are separated by the plateportions 52 as separation walls, which may be regarded as flat-shapedplate portions of unit plate members 50 and 51. The multilayer core unit65 has a configuration in which the number of layers of the reformingpassages 18 and the number of layers of the combustion passages 20differ from each other. Specific description will be given below.

The unit plate member 50 includes the plate portion 52 formed in a flatshape. As shown in FIG. 9, the plate portion 52 is formed by providing,at both ends in the longitudinal direction of the parallel flow portion52 as the heat exchanging section, which is formed in the rectangularshape, the flow direction-changing sections 52B and 52C, individually,in a continuous manner, when viewed from above. In this embodiment, theflow direction-changing sections 52B and 52C are formed in a triangularshape such that the bases thereof are made to coincide with thecorresponding short sides of the parallel flow portion 52A (with arectangular shape). Accordingly, the plate portion 52 as a whole isformed in a substantially hexagonal shape. Each unit plate member 50includes the outer walls 54, which are provided in a standing conditionat edges of the plate portion 52 on the side thereof on which thereforming passages 18 are formed.

The outer walls 54 are provided in a standing condition all around theplate portion 52 except one side portion of each of thedirection-changing sections 52B and 52C, so that the outer walls 54function as spacers that define the reforming passages 18 between thestacked unit plate members 50 and 51, and also function as outer wallsthat prevent the outflow of gas from the reforming passages 18, and, atthe same time, create the gas inlet 50A on the flow-direction changingsection 52B-side, and the gas outlet SOB on the flow-direction changingsection 52C-side. The gas inlet 50A and the gas outlet 50B are formedsymmetrically with respect to the centroid of the plate portion 52, andthe openings thereof are oriented in the directions indicated by thearrows C1 and C2, respectively, which are opposite to the direction ofthe parallel flow portion 52A, which extends along the longitudinaldirection of the outer walls 54, in the flow-direction changing sections52B and 52C.

A plurality of standing walls (partition walls) 56 that divide thereforming passage 18 into a plurality of parallel passages are providedin a standing condition on the side of the plate portion 52 of the unitplate members 50 on which the reforming passage 18 is formed. Thestanding walls 56 are made substantially parallel with the outer walls54 from the gas inlet 50A to the gas outlet 50B, and are configured soas to divide the reforming passage 18 into the plurality of dividedpassages (microchannels) 58. Each divided passage 58 is formed in acrank-like shape such that the length of the passages from the gas inlet50A to the gas outlet SOB is substantially the same owing to thesymmetrical arrangement of the gas inlet 50A and the gas outlet 50Bdescribed above.

The part of the divided passages 58 in the parallel flow portion 52Athat are separated by partition wall portions 56A of the standing walls56 lying along the longitudinal direction of the parallel flow portions52A, serve as heat-exchanging passages 58A. Meanwhile, the part of thedivided passages 58 between which inlet guide walls 56B are provided onthe flow-direction changing section 52B in a standing condition, serveas reformation material guide passages 58B constituting a reformationmaterial guide section. The inlet guide walls 56B are part of thestanding walls 56, and lie along the direction indicated by the arrowC1. In addition, the part of the divided passages 58 between whichoutlet guide walls 56C are provided on the flow-direction changingsection 52C in a standing condition, serve as reformate gas guidepassages 58C constituting a reformate gas guide section. The outletguide walls 56C are part of the standing walls 56, and lie along thedirection indicated by the arrow C2.

The unit plate member 51 includes the plate portion 52 that has the sameshape as that of the plate portion 52 constituting the unit plate member50, and includes the outer walls 60, which are provided in a standingcondition at the periphery of the plate portion 52 on the side thereofon which the combustion passages 20 are formed. The outer walls 60 areprovided in a standing condition all around the plate portion 52 exceptone side portion of each of the direction-changing sections 52B and 52C,so that the outer walls 60 function as spacers that form the combustionpassages 20 between the stacked unit plate members 50 and 51, and alsofunction as outer walls that prevent the outflow of gas from thecombustion passages 20, and so that the outer walls 60 form the gasinlet 51A on the flow-direction changing section 52B-side, and the gasoutlet 51B on the flow-direction changing section 52C-side.

The gas inlet 51A is formed on the same side of a parallel flow portion52A in the longitudinal direction as the gas inlet 50A of the unit platemember 50 (that is, on the side indicated by the arrow A in FIG. 9) soas to be open toward the direction indicated by the arrow D1, which isdifferent from the direction indicated by the arrow C1 (that is, whichis symmetric with respect to the longitudinal axis of the parallel flowportion 52A). Meanwhile, the gas outlet 51B is formed on the same sideof a parallel flow portion 52A in the longitudinal direction as the gasinlet 50A of the unit plate member 50 (that is, on the side indicated bythe arrow B in FIG. 9) so as to be open toward the direction indicatedby the arrow D2, which is different from the direction indicated by thearrow C2 (that is, which is symmetric with respect to the longitudinalaxis of the parallel flow portion 52A), toward which the gas outlet SOBis open.

The plurality of standing walls (partition walls) 62 that divide thecombustion passage 20 into a plurality of parallel passages are providedin a standing condition on the combustion passage 20-formed-side of theplate portion 52 of the unit plate members 51. The standing walls 62 aremade substantially parallel with the outer walls 60 from the gas inlet51A to the gas outlet 51B, and are configured so as to divide thecombustion passage 20 into the plurality of divided passages(microchannels) 64. Each divided passage 64 is formed in a crank-likeshape such that the length of the passages from the gas inlet 51A to thegas outlet 51B is substantially the same owing to the symmetricalarrangement of the gas inlet 51A and the gas outlet 511B describedabove.

In the divided passages 64, the portions in the parallel flow portion52A that are separated by partition wall portions 62A of the standingwalls 62 lying along the longitudinal direction of the parallel flowportions 52A, are made to serve as heat-exchanging passages 64A.Meanwhile, the part of the divided passages 64 that are created byproviding, as part of the standing walls 62, inlet guide walls 62B onthe flow-direction changing section 52B in a standing condition that liealong the direction indicated by the arrow D1, are made to serve asmixed gas guide passages 64B constituting a fuel guide section. Inaddition, the part of the divided passages 64 that are created byproviding, as part of the standing walls 62, outlet guide walls 62C on aflow-direction changing section 52C in a standing condition that liealong the direction indicated by the arrow D2, are made to serve ascombustion exhaust gas guide passages 64C constituting a combustionexhaust gas guide section.

In the heat exchange reformer unit 10 described above, the multilayercore unit 65 is constructed by stacking the unit plate members 50 and 51in the following manner: the gas inlets 50A and 51A are positioned onthe same side (that is, on the side indicated by the arrow A) of theparallel flow portion 52A (the heat-exchanging passages 58A and 64A),and the gas outlets 50B and 51B are positioned on the same side (thatis, on the side indicated by the arrow B) of the parallel flow portion52A as described above, so that the directions in which gas flows in theheat-exchanging passages 58A and 64A on the respective layers are set tothe same direction (the direction indicated by the arrow F).

As shown in FIGS. 8A and 9, in this embodiment, the multilayer core unit65 is constructed by stacking two unit plate members 50 (two layers ofthe reforming passages 18) per one unit plate member 51 (one layer ofthe combustion passage 20). Specifically, in the multilayer core unit65, by stacking the units, in each of which two unit plate members 50are stacked on the same side of one unit plate member 51, or the units,in each of which one unit plate member 51 is sandwiched between the unitplate members 50 in the stacking direction, two layers of the reformingpassages 18 are disposed between a pair of the combustion passages 20such that a combustion passage 20 is not adjacent to another combustionpassage 20 in the stacking direction, as shown in FIG. 8B. Accordingly,in the multilayer core unit 65, the reforming passage 18 of each layeris, on any one side thereof, adjacent to a combustion passage 20 with aplate portion 52 interposed therebetween.

In each of the unit plate members 50 and 51 described above, theportions (the plate portion 52, the outer walls 54 and the standingwalls 56; or the plate portion 52, the outer walls 60 and the standingwalls 62) are integrally formed of metallic materials, such as stainlesssteel, or solid (not porous) ceramics, for example. The plurality of theunit plate members 50 and the plurality of the unit plate members 51constitute the multilayer core unit 65 of the heat exchange reformerunit 10, wherein the plate members 52 and the outer walls 54 and 60 (thestanding walls 56 and 62) are airtightly joined by brazing using brazingfiller or by diffusion bonding, for example. As shown in FIG. 10, in theheat exchange reformer unit 10, in this embodiment, a flat-shaped plateportion 52 (cover) on which the outer walls 54 or the like are notprovided in a standing condition is placed on the top of the heatexchange reformer unit 10 so as to close the reforming passage 18.

As shown in FIG. 10, a reformation inlet manifold 66 that defines acollection space to which the gas inlets 50A of the respective layersare open is connected to the multilayer core unit 65. In addition, areformation outlet manifold 68 that defines a collection space to whichthe gas outlets 50B of the respective layers are open is connected tothe multilayer core unit 65. Moreover, a combustion inlet manifold 70that defines a collection space to which the gas inlets 51A of therespective layers are open is connected to the multilayer core unit 65.Furthermore, a combustion outlet manifold 72 that defines a collectionspace to which the gas outlets 51B of the respective layers are open isconnected to the multilayer core unit 65. Each of the manifolds 66, 68,70 and 72 is formed in a rectangular tube shape, and one open endthereof is joined to the end portions of the top and bottom plateportions 52, and the end portions of the outer walls 54 and 60 of therespective layers by brazing, for example.

Although not shown in the figures, the material inlet 18A and the steaminlet 18C for introducing reformation material (hydrocarbon) and steam(cathode off-gas), respectively, are provided in the reformation inletmanifold 66, and the reformate gas outlet 19B for discharging reformategas is provided in the reformation outlet manifold 68. Meanwhile, thefuel inlet 20A for introducing mixed gas from the gas mixer 33 isprovided in the combustion inlet manifold 70, and the exhaust gas outlet20B for discharging combustion exhaust gas is provided in the combustionoutlet manifold 72.

In the heat exchange reformer unit 10 (multilayer core unit 65)described above, the reforming catalyst 22 is supported on the innersurface of the divided passages 58 on the unit plate member 50, and theoxidizing catalyst 24 is supported on the inner surface of the dividedpassages 64 on the unit plate member 51. As shown in FIG. 4, which is anexploded plan view in which the illustration of the standing walls 56and 62 is omitted, the reforming catalyst 22 is supported in the dividedpassages 58 (reforming passage 18) in a predetermined region thereofthat does not include part of the divided passages 58 on the gas inlet50A-side, and the oxidizing catalyst 24 is supported in the dividedpassages 58 (combustion passage 20) in a predetermined region thereofthat does not include part of the divided passages 64 on the gas inlet51A-side.

More specifically, with regard to the reforming catalyst 22, anupstream-side supporting region end 22A that is the end on the upstreamside (that is, on the side indicated by the arrow A) in the gas flowdirection in which the reformation material is supplied, substantiallycoincides with the border between the heat-exchanging passages 58A(parallel flow section 52A) and the reformation material guide passages58B (flow direction-changing section 52B) of the divided passages 58.With regard to the oxidizing catalyst 24, an upstream-side supportingregion end 24A that is the end on the upstream side (that is, on theside indicated by the arrow A) in the gas flow direction, in which thefuel is supplied, substantially coincides with the border between theheat-exchanging passages 64A (parallel flow section 52A) and the mixedgas guide passages 64B (flow-direction changing section 52B) of thedivided passages 64. It should be noted that the upstream-sidesupporting region end 24A of the oxidizing catalyst 24 coincides withthe upstream-side supporting region end 22A of the reforming catalyst22, or is positioned a bit further downstream than the upstream-sidesupporting region end 22A.

Next, the operations of the second embodiment will be described.

In the fuel cell system 11 with the above construction, operating thematerial pump 26 and the cathode air pump 36 causes hydrocarbon materialand steam (cathode off-gas) to be introduced into the reforming passages18 of the heat exchange reformer unit 10 through the material supplyline 28. In the reforming passages 18 of the heat exchange reformer unit10, the reforming reactions including the steam-reforming reactionexpressed by the equation (1) and the partial oxidation reactionexpressed by the equation (2) (see the above equations (1) to (4)) arecaused by bringing the introduced hydrocarbon material and steam intocontact with the reforming catalyst 22 with heat supplied from thecombustion passages 20, so that reformate gas that contains hydrogen inhigh concentration is produced.

The reformate gas produced in the reforming passages 18 is supplied tothe anode electrode 14 through the fuel inlet 14A of the anode electrode14. In the fuel cell 12, hydrogen in the reformate gas supplied to theanode electrode 14 is turned into protons, and the protons migrate tothe cathode electrode 16 through the electrolyte to react with oxygen inthe air introduced onto the cathode electrode 16. As the protons migratein this way, electrons flow from the anode electrode 14 toward thecathode electrode 16 through the external conductor, so, thatelectricity is generated.

In the fuel cell 12, the generation of electricity uses hydrogen in thereformate gas supplied to the anode electrode 14 and oxygen in thecathode air supplied to the cathode electrode 16 in accordance with theamount of electricity generated (the electric power consumption of aload), and water (steam under operating temperature conditions) isproduced at the cathode electrode 16. The gas that contains steam isexpelled from the cathode electrode 16 to the steam supply line 40 ascathode off-gas as described above, and introduced into the reformingpassage 18 through the steam inlet 18C.

The gas resulting after hydrogen in the reformate gas is used accordingto the amount of generated electricity as electricity is generated, isdischarged from the anode electrode 14 as anode off-gas. The anodeoff-gas is supplied to the combustion passages 20 of the heat exchangereformer unit 10 through the anode off-gas line 32. In addition, thecoolant off-gas after cooling the fuel cell 12 is supplied to thecombustion passages 20 through the combustion-supporting gas supply line46. In the combustion passages 20, catalytic combustion is caused bybringing the combustible components in the anode off-gas, which is fuel,into contact with the oxidizing catalyst 24 together with the oxygen inthe coolant off-gas as the combustion-supporting gas. The heat producedby the catalytic combustion is supplied to the reforming passages 18through the plate portions 52. Using the heat, in the reforming passages18, the reforming reactions, which are endothermic reactions, aremaintained, and the operating temperature (reformate gas temperature) ismaintained at a temperature required to bring about reforming reactions.

In this way, the fuel cell system 11 supplies hydrocarbon material tothe heat exchange reformer unit 10, and effectively uses various exhaustgases of the fuel cell 12 (the cathode off-gas that contains steam, theanode off-gas that contains combustible components, and the coolantoff-gas that contains oxygen) to maintain the operation of the heatexchange reformer unit 10, which produces hydrogen that is supplied tothe fuel cell 12.

Because the combustion reactions in the combustion passage 20 have highreaction velocities, a reaction field is mainly created on the fuelinlet side, that is, on the upstream-side supporting region end 24A-sideof the region in which the oxidizing catalyst 24 is supported, as shownin FIG. 11. On the other hand, the reforming reactions in the reformingpassage 18 (the reactions, the main reaction of which is steam-reformingreaction) have reaction velocities significantly slower than those ofthe combustion reactions, and therefore, a reaction field of reformingreactions is created (maintained) from the material inlet 18A (theupstream-side supporting region end 22A of the reforming catalyst 22) upto the vicinity of the reformate gas outlet 18B. Accordingly, theknowledge that the amount of the reforming reaction that can be carriedout in a unit volume of space is less than the amount of the combustionreaction that take place in the unit volume of space has been obtained.

In the heat exchange reformer unit 10, the number of the stacked layers(channels) of the reforming passages 18 is larger than the number of thestacked layers of the combustion passages 20. Thus, the increase in thevolume (ratio) of the reforming passage 18 (divided passages 58) isachieved while keeping the overall volume (the sum of the total volumeof the reforming passages 18 and the total volume of the combustionpassages 20) unchanged. As a result, in the heat exchange reformer unit10, the total amount of the reforming reaction in the reforming passages18 and the total amount of the combustion reaction in the combustionpassages 20 are matched (the amount of reforming reaction and the amountof combustion reaction are set according to the reforming reactionfield), which realizes the operation at high space velocities, Assumingthat the overall volume (m³) of the heat exchange reformer unit 10 isVa, the feed flow rate of the reformation material is Qr (m³/h), thetotal volume of the reforming passages 18 (all the divided passages 58)is Vr, and the total volume of the combustion passages 20 (all thedivided passages 64) is Vc, the space velocity SV is defined by theequation, SV(1/h)=Qr/Va=Qr/(Vr+Vc). The operations and effects of theheat exchange reformer unit 10 will be described while comparing it witha comparative example shown in FIGS. 22A and 22B.

A heat exchange reformer unit 200 according to the comparative exampleshown in FIGS. 22A and 22B is constructed by alternately stackingreforming passages 18 and combustion passages 20. Accordingly, in theheat exchange reformer unit 200, the ratio of the volume of thereforming passages 18 to the volume of the heat exchange reformer unit200 (overall volume) is about 50% (see the “ 1/1” (layer ratio) bar inthe graph of FIG. 12). Meanwhile, the reforming reactions, which havelow reaction velocities as mentioned above, require a certain reactionspace. Accordingly, it is difficult to achieve a high space velocity forreformation material by using the heat exchange reformer unit 200.Specifically, when the amount of reformation material supplied to thereforming passages 18 is increased to realize operation at high spacevelocities, the speed of flow of gas in the reforming passages 18 isincreased. As a result, the time for reaction (reaction field) of thereforming reactions, which have low reaction velocities, cannot besecured, and the reforming efficiency is therefore reduced.

On the other hand, in the heat exchange reformer unit 10, two layers ofthe reforming passages 18 are stacked per one layer of the combustionpassage 20, so that the ratio of the volume of the reforming passages 18to the overall volume of the heat exchange reformer unit 10 increases toabout 67% as shown in FIG. 12 (see the “2/1” (layer ratio) bar in thegraph). In addition, because the volume of the reforming passage 18 perlayer is constant in the heat exchange reformer unit 10 in which themultilayer core unit 65 is formed by stacking the unit plate members 50and 51, the inner surface area of the reforming passages 18, that is,the area of the region, in which the reforming catalyst 22 is supported,that is, the amount of catalyst supported, increases by about 34% ascompared to the heat exchange reformer unit 200 that has the layer ratioof 1/1 (see the “ 1/1” (layer ratio) bar in the graph of FIG. 13), asshown in FIG. 13 (see the “ 2/1” (layer ratio) bar in the graph).

As described above, with the heat exchange reformer unit 10, a higherspace velocity as compared to that of the heat exchange reformer unit200 is achieved, that is, a construction with which operation at highspace velocities (increase in the amount of reformation materialsupplied) contributes to the improvement of the reforming efficiency, isrealized. FIG. 14 shows a relation between the proportion of the regionoccupied by the reforming passages 18 (volume, or the surface area ofthe region in which the reforming catalyst 22 is supported) and theconversion ratio (reformation ratio) when the space velocity is constant(about 50000/h). The conversion ratio represents the proportion in whichthe hydrocarbon, which is reformation material, is converted into carbonmonoxide, carbon dioxide, or methane. When the steam-reforming reactionexpressed by the above equation (1) is completely carried out (that is,when the amount of hydrocarbon other than methane in the reformate gasis zero), the conversion ratio is defined as one (100%).

As shown in FIG. 14, under the operating conditions in which thetemperature of the reformate gas at the outlet is 650° C., theconversion ratio of the heat exchange reformer unit 10 (in which theratio of the volume occupied by the reforming passages 18 is 67%) isimproved by about 10% as compared to that of the heat exchange reformerunit 200 (in which the same volume ratio is 50%).

In this way, the heat exchange reformer unit 10 according to the secondembodiment improves the reforming efficiency.

Next, other embodiments of the present invention will be described. Itshould be noted that basically the same components/portions as those ofthe second embodiment, or the foregoing construction are denoted by thesame reference numerals as those of the second embodiment, or theforegoing construction, and the description thereof will be omitted. Insome cases, the illustration thereof will also be omitted.

Third Embodiment

FIG. 15A shows a heat exchange reformer unit 80 according to a thirdembodiment in a front view in section corresponding to FIG. 8A. As shownin FIG. 15A, the heat exchange reformer unit 80 differs from the heatexchange reformer unit 10, which includes the multilayer core unit 65 inwhich two layers of the reforming passages 18 are stacked per one layerof the combustion passage 20, in that the heat exchange reformer unit 80includes a multilayer core unit 82 in which three unit plate members 50(three layers of the reforming passages 18) are stacked per one unitplate member 51 (one layer of the combustion passage 20).

Specifically, in the multilayer core unit 82, three layers of thereforming passages 18 are disposed between a pair of the combustionpassages 20, as shown in FIG. 15B, by stacking the units, in each ofwhich three unit plate members 50 are stacked on the same side of oneunit plate member 51. Accordingly, in the multilayer core unit 82, onelayer of the reforming passage 18 is disposed so as to be sandwichedbetween two layers of the reforming passages 18 each of which is, on anyone side thereof, adjacent to a combustion passage 20 with a plateportion 52 interposed therebetween, that is, so as not to be adjacent tothe combustion passage 20 on either side of the reforming passage 18.

As described above, in the multilayer core unit 82 in which three layersof the reforming passages 18 are stacked per one layer of the combustionpassage 20, the ratio of the volume of the reforming passages 18 to theoverall volume is about 75% as shown in FIG. 12 (see the “ 3/1” bar inthe graph). In addition, because the volume of one layer of thereforming passage 18 is constant in the heat exchange reformer unit 80,the inner surface area, that is, the catalyst-supporting region area(supporting amount), of the combustion passages 20 is increased by about50% as compared to that of the heat exchange reformer unit 200 (see the“1/1” bar (layer ratio) in the graph).

In the other points, the configuration of the heat exchange reformerunit 80 is the same as that of the heat exchange reformer unit 10.Accordingly, as in the case of the heat exchange reformer unit 10according to the second embodiment, the heat exchange reformer unit 80according to the third embodiment also makes it possible to match thetotal amount of the reforming reaction in the reforming passages 18 andthe total amount of the combustion reaction in the combustion passages20 (that is, to set the amount of reforming reaction and the amount ofcombustion reaction according to the reforming reaction field), and highspace velocities are therefore achieved. That is, it is possible toimprove reforming efficiency.

In FIG. 14, results showing that the conversion ratio of the heatexchange reformer unit 80 (in which the ratio of the volume occupied bythe reforming passages 18 is 75%) (see the open symbols) is less thanthat of the heat exchange reformer unit 10 (in which the same volumeratio is 67%) are shown. It is likely that this results from the factthat the thermal performance of the heat exchange reformer unit 80 islower than that of the heat exchange reformer unit 10 because the heattransport distance from a combustion passage 20 to the reforming passage18 that is not adjacent to any combustion passages 20 on either side ofthe reforming passage 18, and at the same time, heat is transported fromone layer of the combustion passage 20 to one and a half layer of thereforming passages 18 on each side of the combustion passage 20 (tothree layers in total). That is, because of the reduction in the thermalperformance (heat transfer-controlled effect), the conversion ratio isreduced as compared to that of the heat exchange reformer unit 10 underthe operating conditions in which the space velocity is high and thetemperature of the reformate gas is 650° C.

It is not illustrated herein but has been experimentally confirmed that,under the operating conditions in which, for example, the reformingreaction velocity is low (a larger reaction space is required), such aswhen the reformation material temperature is low, the effect of theincrease in the volume of the reforming passages 18 (the surface area ofthe region in which the reforming catalyst 22 is supported) surpassesthe effect of the reduction in the thermal performance, and theconversion ratio of the heat exchange reformer unit 80 is significantlygreater than the conversion ratio of the heat exchange reformer unit 10.

Fourth Embodiment

FIG. 16A shows a front view in section of a heat exchange reformer unit90 according to a fourth embodiment. FIG. 16B shows a plan view of thereforming passage 18 (combustion passage 20) constituting the heatexchange reformer unit 90. As shown in these figures, the heat exchangereformer unit 90 differs from the heat exchange reformer unit 80 inincluding a multilayer core unit 94 in which such unit plate members 50and 51 as described below are stacked. Specifically, in the unit platemember 50, heat transfer-supporting ribs 92, which constitutes heattransfer-promoting portions, are provided in a standing conditionbetween the end portions of the standing walls 56 on the gas inlet50A-side thereof, and in unit plate members 51, heat transfer-supportingribs 92, which constitutes heat transfer-promoting portions, areprovided in a standing condition between the end portions of thestanding walls 62 on the gas inlet 51A-side thereof.

In the fourth embodiment, the heat transfer-supporting ribs 92 areprovided on the plate portions 52 in twos between the adjacent standingwalls 56 (including between an outer wall 54 and the adjacent standingwall 56) and between the adjacent standing walls 62 (including betweenan outer wall 60 and the adjacent standing wall 62) in a standingcondition so that the height of the standing walls 56 and 62 are equalto each other. The portions at which the heat transfer-supporting ribs92 are provided in a standing condition are set substantiallycorresponding to the reaction field in which the combustion reactionsmainly occur in the combustion passages 20, that is, the region in whicha large amount of heat is generated.

When the plate portions 52 between the layers are regarded as heattransfer fins, wherein the width of the fin is W, the thickness of theconnecting portions (the standing wall 56, the standing wall 64 and theheat transfer-supporting rib 92) is d, and the thermal conductivity is?, as shown in FIG. 17, providing the heat transfer-supporting ribs 92causes the multilayer core unit 94 to have a configuration in which thewidth W is reduced as compared to that of the third embodiment. Whenthese are compared in terms of the fin efficiency shown in FIG. 18,while the fin efficiency of the multilayer core unit 82 of the heatexchange reformer unit 80 is 0.89, the fin efficiency of the multilayercore unit 94 of the heat exchange reformer unit 90 is enhanced to 0.98.The arrows in FIG. 17 show heat transfer paths.

In the other points, the configuration of the heat exchange reformerunit 80 is the same as that of the heat exchange reformer unit 10.Accordingly, as in the case of the heat exchange reformer unit 10according to the second embodiment, the heat exchange reformer unit 90according to the fourth embodiment also makes it possible to match thetotal amount of the reforming reaction in the reforming passages 18 andthe total amount of the combustion reaction in the combustion passages20 (that is, to set the amount of reforming reaction and the amount ofcombustion reaction according to the reforming reaction field), and highspace velocities are therefore achieved. That is, it is possible toimprove reforming efficiency.

In the heat exchange reformer unit 90, the heat transfer-supporting ribs92 promote heat transfer from the combustion passages 20 to thereforming passages 18, especially to the reforming passages 18 that arenot adjacent to the combustion passages 20 on either side of eachreforming passage 18, which cancels out the reduction in the thermalefficiency (heat-transfer controlled effect) caused in the case of thethird embodiment. Thus, in the heat exchange reformer unit 90 (in whichthe ratio of the volume occupied by the reforming passages 18 is 75%),the conversion ratio exceeding that of the heat exchange reformer unit10 is achieved under the operating conditions in which the spacevelocity is high and the temperature of the reformate gas is 650° C., asshown by the solid symbols in FIG. 14. That is, by virtue of thepromotion of heat transfer by the heat transfer-supporting ribs 92, itis achieved to make the increase in the volume of the reforming passages18 (the surface area of the region in which the reforming catalyst 22 issupported) contribute to the improvement in the conversion ratio. Inaddition, because the region in which the heat transfer-supporting ribs92 are disposed is limited to the end portions on the gas inlet50A-side, or 51A-side, it is made possible to minimize the increase inthe pressure loss relative to that of the heat exchange reformer unit80.

Fifth Embodiment

FIG. 19A shows a heat exchange reformer unit 100 according to a fifthembodiment in a front view in section. FIG. 19B shows the reformingpassages 18 (combustion passages 20) constituting the heat exchangereformer unit 100 in a plan view. As shown in these figures, the heatexchange reformer unit 100 differs from the heat exchange reformer unit80 in including a multilayer core unit 104 in which such unit platemembers 50 and 51 as described below are stacked. Specifically, in theunit plate members 50 and 51, end portions of the standing walls 56 onthe gas inlet 50A-side, and end portions of the standing walls 62 on thegas inlet 51A-side are formed into heat transfer-supporting thickportions 102 as heat transfer-promoting portions, which are thicker thanthe remaining portions of the standing walls 56 and 62.

The heat transfer-supporting thick portions 102 are set substantiallycorresponding to the reaction field in which the combustion reactionsmainly occur in the combustion passages 20, that is, the region in whicha large amount of heat is generated. Thus, when regarded as heattransfer fins shown in FIG. 17, the multilayer core unit 94 is renderedto have a configuration in which the thickness d of the connectingportions between the plate portions 52 are increased as compared to thatof the third embodiment, by providing the heat transfer-supporting thickportions 102. When these are compared in terms of the fin efficiencyshown in FIG. 18, while the fin efficiency of the multilayer core unit82 of the heat exchange reformer unit 80 is 0.89, the fin efficiency ofthe multilayer core unit 104 of the heat exchange reformer unit 100 isenhanced to 0.99.

In the other points, the configuration of the heat exchange reformerunit 100 is the same as that of the heat exchange reformer unit 80.Accordingly, as in the case of the heat exchange reformer unit 10according to the second embodiment, the heat exchange reformer unit 100according to the fifth embodiment also makes it possible to match thetotal amount of the reforming reaction in the reforming passages 18 andthe total amount of the combustion reaction in the combustion passages20 (that is, to set the amount of reforming reaction and the amount ofcombustion reaction according to the reforming reaction field), and highspace velocities are therefore achieved. That is, it is possible toimprove reforming efficiency.

In the heat exchange reformer unit 100, the heat transfer-supportingthick portions 102 promote heat transfer from the combustion passages 20to the reforming passages 18, especially to the reforming passages 18that are not adjacent to the combustion passages 20 on either side ofeach reforming passage 18, which cancels out the reduction in thethermal performance (heat-transfer controlled effect) caused in the caseof the third embodiment. Thus, in the heat exchange reformer unit 100(in which the ratio of the volume occupied by the reforming passages 18is 75%), the conversion ratio exceeding that of the heat exchangereformer unit 10 is achieved under the operating conditions in which thespace velocity is high and the temperature of the reformate gas is 650°C., as shown by the solid symbols in FIG. 14. That is, by virtue of thepromotion of heat transfer by the heat transfer-supporting thickportions 102, it is achieved to make the increase in the volume of thereforming passages 18 (the surface area of the region in which thereforming catalyst 22 is supported) contribute to the improvement in theconversion ratio. In addition, because the region in which the heattransfer-supporting thick portions 102 are provided is limited to theend portions on the gas inlet 50A-side, or 51A-side, it is made possibleto minimize the increase in the pressure loss relative to that of theheat exchange reformer unit 80.

Sixth Embodiment

FIG. 20 shows a heat exchange reformer unit 110 according to a sixthembodiment in a front view in section. As shown in this figure, the heatexchange reformer unit 110 differs from the heat exchange reformer unit80 in including a multilayer core unit 116 that has, instead of part ofthe plate portions 52 and the standing walls 56 constituting the unitplate member 50, plate portions 112 and standing walls 114 bothconstituting heat transfer-promoting portions made of material (highlyheat-conductive steel) having a thermal conductivity higher than that ofthe plate portions 52 and the standing walls 56.

The plate portion 112 is disposed except at the portions constitutingthe combustion passages 20, in other words, so as to separate thereforming passages 18 that are adjacent to each other in the stackingdirection. The standing walls 114 are disposed at the positions suchthat the reforming passage 18 that is adjacent to a combustion passage20 is divided into the divided passages 58. In FIG. 20, only the plateportions 112 and the standing walls 114 out of the components of theunit plate members 50 and 51 are hatched.

Thus, when regarded as heat transfer fins shown in FIG. 17, themultilayer core unit 116 is rendered to have a configuration in whichthe thermal conductivity ? of each separation wall between the reformingpassages 18 that are adjacent to each other in the stacking direction,and connecting portions having the thickness d is increased as comparedto that of the third embodiment, by providing the plate portions 112 andthe standing walls 114. When these are compared in terms of the finefficiency shown in FIG. 18, while the fin efficiency of the multilayercore unit 82 of the heat exchange reformer unit 80 is 0.89, the finefficiency of the multilayer core unit 116 of the heat exchange reformerunit 110 is enhanced to 0.99.

In the other points, the configuration of the heat exchange reformerunit 110 is the same as that of the heat exchange reformer unit 80.Accordingly, as in the case of the heat exchange reformer unit 10according to the second embodiment, the heat exchange reformer unit 110according to the sixth embodiment also makes it possible to match thetotal amount of the reforming reaction in the reforming passages 18 andthe total amount of the combustion reaction in the combustion passages20 (that is, to set the amount of reforming reaction and the amount ofcombustion reaction according to the reforming reaction field), and highspace velocities are therefore achieved.

In the heat exchange reformer unit 110, the plate portions 112 and thestanding walls 114 promote heat transfer from the combustion passages 20to the reforming passages 18, especially to the reforming passages 18that are not adjacent to the combustion passages 20 on either side ofeach reforming passage 18, which cancels out the reduction in thethermal efficiency (heat-transfer controlled effect) caused in the caseof the third embodiment. Thus, in the heat exchange reformer unit 110(in which the ratio of the volume occupied by the reforming passages 18is 75%), the conversion ratio exceeding that of the heat exchangereformer unit 10 is achieved under the operating conditions in which thespace velocity is high and the temperature of the reformate gas is 650°C., as shown by the solid symbols in FIG. 14. That is, by virtue of thepromotion of heat transfer by the plate portions 112 and the standingwalls 114, it is achieved to make the increase in the volume of thereforming passages 18 (the surface area of the region in which thereforming catalyst 22 is supported) contribute to the improvement in theconversion ratio. In addition, because the plate portions 112 and thestanding walls 114 do not change of the cross-sectional area of thereforming passages 18, the increase in the pressure loss relative tothat of the heat exchange reformer unit 80 is avoided.

Seventh Embodiment

FIG. 21A shows a heat exchange reformer unit 120 according to a seventhembodiment in a front view in section corresponding to FIG. 8A. As shownin this figure, the heat exchange reformer unit 120 differs from theheat exchange reformer unit 10 that includes the multilayer core unit 65in which two layers of the reforming passages 18 are stacked per oneunit plate member 50, in including a multilayer core unit 122 in whichfour unit plate members 50 (four layers of the reforming passages 18)are stacked per one unit plate member 51 (one layer of the combustionpassage 20).

Specifically, in the multilayer core unit 122, four layers of thereforming passages 18 are disposed between a pair of the combustionpassages 20, as shown in FIG. 21B, by stacking the units, in each ofwhich four unit plate members 50 are stacked on the same side of oneunit plate member 51. Accordingly, in the multilayer core unit 122, twolayer of the reforming passages 18 are disposed so as to be sandwichedbetween two layers of the reforming passages 18, each of which is, onany one side thereof, adjacent to a combustion passage 20 with a plateportion 52 interposed therebetween in the stacking direction, that is,so as not to be adjacent to the combustion passage 20 on either side ofthe concerned reforming passage 18.

As described above, in the multilayer core unit 122 in which four layersof the reforming passages 18 are stacked per one layer of the combustionpassage 20, the ratio of volume of the reforming passages 18 to theoverall volume is about 80%. In addition, because the volume of onelayer of the reforming passage 18 is constant in the heat exchangereformer unit 120, the inner surface area, that is, thecatalyst-supporting region area (supporting amount), of the combustionpassages 20 is increased by about 60% as compared to that of the heatexchange reformer unit 200.

In the other points, the configuration of the heat exchange reformerunit 120 is the same as that of the heat exchange reformer unit 10.Accordingly, as in the case of the heat exchange reformer unit 10according to the second embodiment, the heat exchange reformer unit 120according to the seventh embodiment also makes it possible to match thetotal amount of the reforming reaction in the reforming passages 18 andthe total amount of the combustion reaction in the combustion passages20 (that is, to set the amount of reforming reaction and the amount ofcombustion reaction according to the reforming reaction field), and highspace velocities are therefore achieved. That is, it is possible toimprove reforming efficiency.

In the heat exchange reformer unit 120, in order to cancel out thereduction in the thermal performance (heat-transfer controlled effect)that results from the necessity to transport heat to two layers of thereforming passages 18 per one layer of the combustion passage 20, theheat transfer-supporting ribs 92, the heat transfer-supporting thickportion 102, or both of the plate portions 112 and the standing walls114 (heat transfer-promoting portion) may be provided.

Although, in the above embodiments, examples are illustrated in whichthe heat exchange reformer unit is used in the fuel cell system, thepresent invention is not limited to these embodiments. The presentinvention is not limited by applications as long as the heat exchangereformer unit is one of various heat exchange reformer units forobtaining gas that contains hydrogen from reformation material.Accordingly, the present invention is not limited by the configurationof the water supply system. For example, a configuration in which awater tank, water pipes, water vaporizer etc. are provided as a watersupply system may be adopted.

In addition, although, in the above embodiments, examples areillustrated in which the heat exchange reformer units 10, 80, 90, 100,110 and 120 are each a parallel-flow heat exchange reformer unit, thepresent invention is not limited to the embodiments. The presentinvention may be applied to a cross-flow heat exchange reformer unit,for example.

Moreover, in the above embodiments, examples are illustrated in whichone layer of the reforming passage 18 and one layer of the combustionpassage 20 have the same volume (cross section of passage), the presentinvention is not limited to the embodiments. A configuration in whichone layer of the reforming passage 18 and one layer of the combustionpassage 20 have different volumes (cross section of passage), forexample.

1-23. (canceled)
 24. A heat exchange reformer unit, comprising: areforming section, in which reforming catalyst for inducing reformingreactions is supported, for producing reformate gas, which containshydrogen, from supplied reformation material through reforming reactionsincluding steam-reforming reaction; a heating section, which is disposedadjacent to the reforming section with a separation wall interposedbetween the heating section and the reforming section so as to cause agas flow in the same direction as that of a gas flow in the reformingsection, and in which oxidizing catalyst for catalytic combustion issupported, for supplying, to the reforming section, heat generated bycatalytically burning supplied fuel; a reformation material-introducingsection, one end of which serves as a supply port of the reformationmaterial, and the other end of which is integral with a reformationmaterial inflow side of the reforming section; a fuel-introducingsection, one end of which serves as a supply port of the fuel, and theother end of which is integral with a fuel inflow side of the heatingsection, for introducing the fuel into the heating section in a flowdirection different from a flow direction of the reformation material inthe reformation material-introducing section; and a cross-flow heatexchanging section which is constituted by the reformation materialintroducing section and the fuel-introducing section, and which does notsupport a catalyst, wherein a plurality of the reforming sections and aplurality of the heating sections are provided, wherein the plurality ofthe reforming sections and the plurality of the heating sections arestacked with at least part of the plurality of the reforming sectionsbeing adjacent to at least part of the plurality of the heatingsections.
 25. The heat exchange reformer unit according to claim 24,wherein the entirety of the fuel-introducing section is a region inwhich no oxidizing catalyst is supported.
 26. The heat exchange reformerunit according to claim 24, wherein the reformation material-introducingsection is provided for each of the reforming sections, and surfaceplanes of the reformation material supply ports are substantially on thesame plane, and wherein the fuel-introducing section is provided foreach of the heating sections, and surface planes of the fuel supplyports are substantially on the same plane.
 27. The heat exchangereformer unit according to claim 26, wherein the heat exchange reformerunit comprises: a plurality of reforming section-forming plate memberseach including: a first flat-shaped plate portion; and a first standingwall provided on the first flat-shaped plate portion in a standingcondition for guiding the reformation material in a predetermineddirection, wherein a first heat exchanging section constituting thereforming section together with another plate portion is formed of partof the first flat-shaped plate portion, and wherein a reformationmaterial guide section constituting the reformation material-introducingsection together with another plate portion is formed of part of thefirst flat-shaped plate portion and the first standing wall that isformed adjacent to a reformation material supply-side of the first heatexchanging section; and a plurality of heating section-forming platemembers each including: a second flat-shaped plate portion; and a secondstanding wall provided on the second flat-shaped plate portion in astanding condition for guiding the fuel in a direction intersecting thepredetermined direction, wherein a second heat exchanging sectionconstituting the heating section together with another plate portion isformed of part of the second flat-shaped plate portion, and wherein afuel guide section constituting the fuel-introducing section togetherwith another plate portion is formed of part of the second flat-shapedplate portion and the second standing wall that is formed adjacent to afuel supply-side of the second heat exchanging section, wherein thereforming section-forming plate members and the heating section-formingplate members are stacked in a predetermined pattern.
 28. The heatexchange reformer unit according to claim 26, further comprising: areformation material manifold, defining a collection space to which thereformation material supply ports of the plurality of the reformationmaterial-introducing sections are open, for distributing the reformationmaterial to the plurality of the reformation material-introducingsections; and a fuel manifold, defining a collection space to which thefuel supply ports of the plurality of the fuel-introducing sections areopen, for distributing the fuel to the plurality of the fuel-introducingsections.
 29. The heat exchange reformer unit according to claim 24,further comprising: a reformate gas-discharging section, one end ofwhich serves as a discharge port of the reformate gas, and the other endof which is integral with a reformate gas outflow side of the reformingsection; and a combustion exhaust gas-discharging section, one end ofwhich serves as a discharge port of combustion exhaust gas of theheating section, and the other end of which is integral with acombustion exhaust gas outflow side of the heating section, forintroducing the combustion exhaust gas to the discharge port of thecombustion exhaust gas in a flow direction different from a flowdirection of the reformate gas in the reformate gas-discharging section.30. The heat exchange reformer unit according to claim 24, wherein aplurality of the reforming sections are provided, and the at least oneheating section is provided so that the heating sections is less innumber than the reforming sections.
 31. The heat exchange reformer unitaccording to claim 24, wherein a plurality of the reforming sections anda plurality of the heating sections are provided, wherein the pluralityof the reforming sections and the plurality of the heating sections arestacked so that a surface area of a region in which the reformingcatalyst is supported is greater than a surface area of a region inwhich the oxidizing catalyst is supported.
 32. The heat exchangereformer unit according to claim 24, wherein a plurality of thereforming sections and a plurality of the heating sections are provided,wherein the plurality of the reforming sections and the plurality of theheating sections are stacked so that an amount of the reforming catalystsupported is greater than an amount of the oxidizing catalyst supported.33. The heat exchange reformer unit according to claim 24, wherein aplurality of the reforming sections and a plurality of the heatingsections are provided, wherein the plurality of the reforming sectionsand the plurality of the heating sections are stacked so that a totalvolume of the plurality of the reforming sections is greater than atotal volume of the plurality of heating sections.
 34. A heat exchangereformer unit, comprising: a plurality of reforming sections forproducing reformate gas, in which reforming catalyst for inducingreforming reactions is supported; and a plurality of heating sections,in which reforming catalyst for catalytic combustion is supported, forsupplying heat, which is generated by catalytically burning suppliedfuel, to the reforming sections, wherein a number of the heatingsections is less in number than a number of the reforming sections. 35.The heat exchange reformer unit according to claim 34, wherein the heatexchange reformer unit includes a part in which two layers of thereforming sections are stacked per one layer of the heating section. 36.The heat exchange reformer unit according to claim 34, wherein the heatexchange reformer unit includes a part in which three layers of thereforming sections are stacked per one layer of the heating section. 37.The heat exchange reformer unit according to claim 34, wherein the heatexchange reformer unit includes a part in which four or more layers ofthe reforming sections are stacked per one layer of the heating section.38. The heat exchange reformer unit according to claim 34, furthercomprising a heat transfer-promoting portion for promoting heat transferfrom the heating section to the adjacent reforming section.
 39. The heatexchange reformer unit according to claim 38, wherein the heattransfer-promoting portion is provided in any one of or each of thereforming section and the heating section in a standing condition,wherein the heat transfer-promoting portion is a standing wall extendingfrom one of separation walls of adjacent reforming section and heatingsection to the other separation wall.
 40. The heat exchange reformerunit according to claim 39, wherein the standing wall is thicker thanthe separation wall between the reforming section and the adjacentheating section.
 41. The heat exchange reformer unit according to claim38, wherein the heat transfer-promoting portion has a thermalconductivity greater than that of a material of which separation wallsforming the heating section are made.
 42. The heat exchange reformerunit according to claim 38, wherein the heat transfer-promoting portionis formed near the vicinity of a supply port of reformation material forproducing reformate gas.
 43. A reformer system, comprising: the heatexchange reformer unit according to claim 34; and a water supply systemfor supplying water to the reforming section of the heat exchangereformer unit.
 44. A heat exchange reformer unit, comprising: aplurality of reforming sections for producing reformate gas, in whichreforming catalyst for inducing reforming reactions is supported; and aplurality of heating sections, in which reforming catalyst for catalyticcombustion is supported, for supplying heat, which is generated bycatalytically burning supplied fuel, to the reforming reactions, whereinthe plurality of the reforming sections and the plurality of the heatingsections are stacked so that a surface area of a region in which thereforming catalyst is supported is greater than a surface area of aregion in which the oxidizing catalyst is supported.
 45. The heatexchange reformer unit according to claim 44, wherein the heat exchangereformer unit includes a part in which two layers of the reformingsections are stacked per one layer of the heating section.
 46. The heatexchange reformer unit according to claim 44, wherein the heat exchangereformer unit includes a part in which three layers of the reformingsections are stacked per one layer of the heating section.
 47. The heatexchange reformer unit according to claim 44, wherein the heat exchangereformer unit includes a part in which four or more layers of thereforming sections are stacked per one layer of the heating section. 48.The heat exchange reformer unit according to claim 44, furthercomprising a heat transfer-promoting portion for promoting heat transferfrom the heating section to the adjacent reforming section.
 49. The heatexchange reformer unit according to claim 48, wherein the heattransfer-promoting portion is provided in any one of or each of thereforming section and the heating section in a standing condition,wherein the heat transfer-promoting portion is a standing wall extendingfrom one of separation walls of adjacent reforming section and heatingsection to the other separation wall.
 50. The heat exchange reformerunit according to claim 49, wherein the standing wall is thicker thanthe separation wall between the reforming section and the adjacentheating section.
 51. The heat exchange reformer unit according to claim48, wherein the heat transfer-promoting portion has a thermalconductivity greater than that of a material of which separation wallsforming the heating section are made.
 52. The heat exchange reformerunit according to claim 48, wherein the heat transfer-promoting portionis formed near the vicinity of a supply port of reformation material forproducing reformate gas.
 53. A reformer system, comprising: the heatexchange reformer unit according to claim 44; and a water supply systemfor supplying water to the reforming section of the heat exchangereformer unit.
 54. A heat exchange reformer unit, comprising: aplurality of reforming sections for producing reformate gas, in whichreforming catalyst for inducing reforming reactions is supported; and aplurality of heating sections, in which reforming catalyst for catalyticcombustion is supported, for supplying heat, which is generated bycatalytically burning supplied fuel, to the reforming reactions, whereinthe plurality of the reforming sections and the plurality of the heatingsections are stacked so that an amount of the reforming catalystsupported is greater than an amount of the oxidizing catalyst supported.55. The heat exchange reformer unit according to claim 54, wherein theheat exchange reformer unit includes a part in which two layers of thereforming sections are stacked per one layer of the heating section. 56.The heat exchange reformer unit according to claim 54, wherein the heatexchange reformer unit includes a part in which three layers of thereforming sections are stacked per one layer of the heating section. 57.The heat exchange reformer unit according to claim 54, wherein the heatexchange reformer unit includes a part in which four or more layers ofthe reforming sections are stacked per one layer of the heating section.58. The heat exchange reformer unit according to claim 54, furthercomprising a heat transfer-promoting portion for promoting heat transferfrom the heating section to the adjacent reforming section.
 59. The heatexchange reformer unit according to claim 58, wherein the heattransfer-promoting portion is provided in any one of or each of thereforming section and the heating section in a standing condition,wherein the heat transfer-promoting portion is a standing wall extendingfrom one of separation walls of adjacent reforming section and heatingsection to the other separation wall.
 60. The heat exchange reformerunit according to claim 59, wherein the standing wall is thicker thanthe separation wall between the reforming section and the adjacentheating section.
 61. The heat exchange reformer unit according to claim58, wherein the heat transfer-promoting portion has a thermalconductivity greater than that of a material of which separation wallsforming the heating section are made.
 62. heat exchange reformer unitaccording to claim 58, wherein the heat transfer-promoting portion isformed near the vicinity of a supply port of reformation material forproducing reformate gas.
 63. A reformer system, comprising: the heatexchange reformer unit according to claim 54; and a water supply systemfor supplying water to the reforming section of the heat exchangereformer unit.
 64. A heat exchange reformer unit, comprising: aplurality of reforming sections for producing reformate gas, in whichreforming catalyst for inducing reforming reactions is supported; and aplurality of heating sections, in which reforming catalyst for catalyticcombustion is supported, for supplying heat, which is generated bycatalytically burning supplied fuel, to the reforming reactions, whereinthe plurality of the reforming sections and the plurality of the heatingsections are stacked so that a total volume of the plurality of thereforming sections is greater than a total volume of the plurality ofheating sections.
 65. The heat exchange reformer unit according to claim64, wherein the heat exchange reformer unit includes a part in which twolayers of the reforming sections are stacked per one layer of theheating section.
 66. The heat exchange reformer unit according to claim64, wherein the heat exchange reformer unit includes a part in whichthree layers of the reforming sections are stacked per one layer of theheating section.
 67. The heat exchange reformer unit according to claim64, wherein the heat exchange reformer unit includes a part in whichfour or more layers of the reforming sections are stacked per one layerof the heating section.
 68. The heat exchange reformer unit according toclaim 64, further comprising a heat transfer-promoting portion forpromoting heat transfer from the-heating section to the adjacentreforming section.
 69. The heat exchange reformer unit according toclaim 68, wherein the heat transfer-promoting portion is provided in anyone of or each of the reforming section and heating section in astanding condition, wherein the heat transfer-promoting portion is astanding wall extending from one of separation walls of adjacentreforming section and heating section to the other separation wall. 70.The heat exchange reformer unit according to claim 69, wherein thestanding wall is thicker than the separation wall between the reformingsection and the adjacent heating section.
 71. The heat exchange reformerunit according to claim 68, wherein the heat transfer-promoting portionhas a thermal conductivity greater than that of a material of whichseparation walls forming the heating section are made.
 72. The heatexchange reformer unit according to claim 68, wherein the heattransfer-promoting portion is formed near the vicinity of a supply portof reformation material for producing reformate gas.
 73. A reformersystem, comprising; the heat exchange reformer, unit according to claim64; and a water supply system for supplying water to the reformingsection of the heat exchange reformer unit.
 74. A reformer system,comprising: the heat exchange reformer unit according to claim 24; and awater supply system for supplying water to the reforming section of theheat exchange reformer unit.